Working with PHP arrays easily

Easy to use and elegant handling for PHP arrays with an array-like map object as offered by jQuery and Laravel Collections.

composer req aimeos/map

Table of contents

• Why PHP Map
• List of methods
  • Create
  • Access
  • Add
  • Aggregate
  • Debug
  • Order
  • Shorten
  • Test
  • Transform
  • Misc
• Documentation
• Custom methods
• Performance
• Upgrade guide

Why PHP Map

Instead of:

$list = [['id' => 'one', 'value' => 'value1'], ['id' => 'two', 'value' => 'value2'], null];
$list[] = ['id' => 'three', 'value' => 'value3'];    // add element
unset( $list[0] );                                   // remove element
$list = array_filter( $list );                       // remove empty values
sort( $list );                                       // sort elements
$pairs = array_column( $list, 'value', 'id' );       // create ['three' => 'value3']
$value = reset( $pairs ) ?: null;                    // return first value

Only use:

$list = [['id' => 'one', 'value' => 'value1'], ['id' => 'two', 'value' => 'value2'], null];
$value = map( $list )                                // create Map
    ->push( ['id' => 'three', 'value' => 'value3'] ) // add element
    ->remove( 0 )                                    // remove element
    ->filter()                                       // remove empty values
    ->sort()                                         // sort elements
    ->col( 'value', 'id' )                           // create ['three' => 'value3']
    ->first();                                       // return first value

You can still use:

$map[] = ['id' => 'three', 'value' => 'value3'];
$value = $map[0];
count( $map );
foreach( $map as $key => value );

Use callbacks:

Also, the map object allows you to pass anonymous functions to a lot of methods, e.g.:

$map->each( function( $val, $key ) {
	echo $key . ': ' . $val;
} );

jQuery style:

If your map elements are objects, you can call their methods for each object and get the result as new map just like in jQuery:

// MyClass implements setStatus() (returning $this) and getCode() (initialized by constructor)

$map = Map::from( ['a' => new MyClass( 'x' ), 'b' => new MyClass( 'y' )] );
$map->setStatus( 1 )->getCode()->toArray();

This will call setStatus( 1 ) on both objects. If setStatus() implementation returns $this, the new map will also contain:

['a' => MyClass(), 'b' => MyClass()]

On those new map elements, getCode() will be called which returns x for the first object and y for the second. The map created from the results of getCode() will return:

['a' => 'x', 'b' => 'y']

Methods

function map function is_map __call __callStatic __construct after all arsort asort before call chunk clear col collapse concat combine copy count countBy dd delimiter diff diffAssoc diffKeys dump duplicates each empty equals every except explode filter find first firstKey flat flip from fromJson get getIterator groupBy has in includes intersect intersectAssoc intersectKeys is isEmpty join keys krsort ksort last lastKey map max merge method min nth offsetExists offsetGet offsetSet offsetUnset only pad partition pipe pop pos prefix pull push random reduce remove replace reverse rsort search sep set shift shuffle skip slice some sort splice split suffix sum take tap times toArray toJson toUrl transpose uasort uksort union unique unshift usort values walk where zip

Create

• function map() : Creates a new map from passed elements
• __construct() : Creates a new map
• copy() : Creates a new copy
• explode() : Splits a string into a map of elements
• from() : Creates a new map from passed elements
• fromJson() : Creates a new map from a JSON string
• times() : Creates a new map by invoking the closure a number of times
• tree() : Creates a tree structure from the list items

Access

• __call() : Calls a custom method
• __callStatic() : Calls a custom method statically
• all() : Returns the plain array
• call() : Calls the given method on all items
• find() : Returns the first/last matching element
• first() : Returns the first element
• firstKey() : Returns the first key
• get() : Returns an element by key
• keys() : Returns all keys
• last() : Returns the last element
• lastKey() : Returns the last key
• pop() : Returns and removes the last element
• pos() : Returns the numerical index of the value
• pull() : Returns and removes an element by key
• random() : Returns random elements preserving keys
• search() : Find the key of an element
• shift() : Returns and removes the first element
• toArray() : Returns the plain array
• unique() : Returns all unique elements preserving keys
• values() : Returns all elements with new keys
• where() : Filters the list of elements by a given condition

Add

• concat() : Adds all elements with new keys
• merge() : Combines elements overwriting existing ones
• pad() : Fill up to the specified length with the given value
• push() : Adds an element to the end
• set() : Overwrites an element
• union() : Adds the elements without overwriting existing ones
• unshift() : Adds an element at the beginning

Aggregate

• count() : Returns the total number of elements
• countBy() : Counts how often the same values are in the map
• max() : Returns the maximum value of all elements
• min() : Returns the minium value of all elements
• sum() : Returns the sum of all values in the map

Debug

• dd() : Prints the map content and terminates the script
• dump() : Prints the map content
• tap() : Passes a clone of the map to the given callback

Order

• arsort() : Reverse sort elements preserving keys
• asort() : Sort elements preserving keys
• krsort() : Reverse sort elements by keys
• ksort() : Sort elements by keys
• reverse() : Reverses the array order preserving keys
• rsort() : Reverse sort elements using new keys
• shuffle() : Randomizes the element order
• sort() : Sorts the elements assigning new keys
• uasort() : Sorts elements preserving keys using callback
• uksort() : Sorts elements by keys using callback
• usort() : Sorts elements using callback assigning new keys

Shorten

• after() : Returns the elements after the given one
• before() : Returns the elements before the given one
• clear() : Removes all elements
• diff() : Returns the elements missing in the given list
• diffAssoc() : Returns the elements missing in the given list and checks keys
• diffKeys() : Returns the elements missing in the given list by keys
• except() : Returns a new map without the passed element keys
• filter() : Applies a filter to the all elements
• intersect() : Returns the elements shared
• intersectAssoc() : Returns the elements shared and checks keys
• intersectKeys() : Returns the elements shared by keys
• nth() : Returns every nth element from the map
• only() : Returns only those elements specified by the keys
• pop() : Returns and removes the last element
• pull() : Returns and removes an element by key
• remove() : Removes an element by key
• shift() : Returns and removes the first element
• skip() : Skips the given number of items and return the rest
• slice() : Returns a slice of the map
• take() : Returns a new map with the given number of items

Test

• function is_map() : Tests if the variable is a map object
• each() : Applies a callback to each element
• empty() : Tests if map is empty
• equals() : Tests if map contents are equal
• every() : Verifies that all elements pass the test of the given callback
• has() : Tests if a key exists
• in() : Tests if element is included
• includes() : Tests if element is included
• is() : Tests if the map consists of the same keys and values
• isEmpty() : Tests if map is empty
• some() : Tests if at least one element is included

Transform

• chunk() : Splits the map into chunks
• col() : Creates a key/value mapping
• collapse() : Collapses multi-dimensional elements overwriting elements
• combine() : Combines the map elements as keys with the given values
• flat() : Flattens multi-dimensional elements without overwriting elements
• flip() : Exchanges keys with their values
• groupBy() : Groups associative array elements or objects
• join() : Returns concatenated elements as string with separator
• map() : Applies a callback to each element and returns the results
• partition() : Breaks the list into the given number of groups
• pipe() : Applies a callback to the whole map
• prefix() : Adds a prefix to each map entry
• reduce() : Computes a single value from the map content
• replace() : Replaces elements recursively
• splice() : Replaces a slice by new elements
• suffix() : Adds a suffix to each map entry
• toJson() : Returns the elements in JSON format
• toUrl() : Creates a HTTP query string
• transpose() : Exchanges rows and columns for a two dimensional map
• traverse() : Traverses trees of nested items passing each item to the callback
• walk() : Applies the given callback to all elements
• zip() : Merges the values of all arrays at the corresponding index

Misc

• delimiter() : Sets or returns the seperator for paths to multi-dimensional arrays
• getIterator() : Returns an iterator for the elements
• method() : Registers a custom method
• offsetExists() : Checks if the key exists
• offsetGet() : Returns an element by key
• offsetSet() : Overwrites an element
• offsetUnset() : Removes an element by key
• sep() : Sets the seperator for paths to multi-dimensional arrays in the current map

Method documentation

is_map() function

Tests if the variable is a map object

function is_map( $var ) : bool

• @param mixed $var Variable to test

Examples:

is_map( new Map() );
// true

is_map( [] );
// false

map() function

Returns a new map for the passed elements.

function map( $elements = [] ) : \Aimeos\Map

• @param mixed $elements List of elements or single value
• @return \Aimeos\Map Map instance

Examples:

Map::from( [] );
// internal: []

Map::from( null );
// internal: []

Map::from( 'a' );
// internal: ['a']

Map::from( new Map() );
// internal: []

Map::from( new ArrayObject() );
// internal: []

__construct()

Creates a new map object.

public function __construct( $elements = [] )

• @param mixed $elements Single element, list of elements, Map object, iterable objects or iterators, everything else

Examples:

new Map();
// internal: []

new Map( [] );
// internal: []

new Map( null );
// internal: []

new Map( 'a' );
// internal: ['a']

new Map( new Map() );
// internal: []

new Map( new ArrayObject() );
// internal: []

__call()

Handles dynamic calls to custom methods for the class.

public function __call( string $name, array $params )

• @param string $name Method name
• @param array $params List of parameters
• @return mixed Result from called function

Calls a custom method added by Map::method(). The called method has access to the internal array by using $this->items.

Examples:

Map::method( 'case', function( $case = CASE_LOWER ) {
    return new self( array_change_key_case( $this->items, $case ) );
} );

Map::from( ['a' => 'bar'] )->case( CASE_UPPER );
// ['A' => 'bar']

This does also allow calling object methods if the items are objects:

$item = new MyClass(); // with method setStatus() (returning $this) and getCode() implemented
Map::from( [$item, $item] )->setStatus( 1 )->getCode()->toArray();

This will call the setStatus() method of each element in the map and use their return values to create a new map. On the new map, the getCode() method is called for every element and its return values are also stored in a new map. This last map is then returned and the map keys from the original map are preserved in the returned map.

If the elements are not objects, they are skipped and if this applies to all elements, an empty map is returned. In case the map contains objects of mixed types and one of them doesn't implement the called method, an error will be thrown.

__callStatic()

Handles static calls to custom methods for the class.

public static function __callStatic( string $name, array $params )

• @param string $name Method name
• @param array $params List of parameters
• @return mixed Result from called function
• @throws \BadMethodCallException

Calls a custom method added by Map::method() statically. The called method has no access to the internal array because no object is available.

Examples:

Map::method( 'foo', function( $arg1, $arg2 ) {} );
Map::foo( $arg1, $arg2 );

after()

Returns the elements after the given one.

public function after( $value ) : self

• @param mixed $value Value or function with (item, key) parameters
• @return self New map with the elements after the given one

The keys are preserved using this method.

Examples:

Map::from( ['a' => 1, 'b' => 0] )->after( 1 );
// ['b' => 0]

Map::from( [0 => 'b', 1 => 'a'] )->after( 'b' );
// [1 => 'a']

Map::from( ['a', 'c', 'b'] )->after( function( $item, $key ) {
    return $item >= 'c';
} );
// [2 => 'b']

all()

Returns the elements as a plain array.

public function all() : array

• @return array Plain array

Examples:

Map::from( ['a'] )->all();
// ['a']

arsort()

Sorts all elements in reverse order and maintains the key association.

public function arsort( int $options = SORT_REGULAR ) : self

• @param int $options Sort options for arsort()
• @return self Updated map for fluid interface

The keys are preserved using this method and no new map is created.

The $options parameter modifies how the values are compared. Possible parameter values are:

• SORT_REGULAR : compare elements normally (don't change types)
• SORT_NUMERIC : compare elements numerically
• SORT_STRING : compare elements as strings
• SORT_LOCALE_STRING : compare elements as strings, based on the current locale or changed by setlocale()
• SORT_NATURAL : compare elements as strings using "natural ordering" like natsort()
• SORT_FLAG_CASE : use SORT_STRING|SORT_FLAG_CASE and SORT_NATURAL|SORT_FLAG_CASE to sort strings case-insensitively

Examples:

Map::from( ['b' => 0, 'a' => 1] )->arsort();
// ['a' => 1, 'b' => 0]

Map::from( ['a', 'b'] )->arsort();
// ['b', 'a']

Map::from( [0 => 'C', 1 => 'b'] )->arsort();
// [1 => 'b', 0 => 'C']

Map::from( [0 => 'C', 1 => 'b'] )->arsort( SORT_STRING|SORT_FLAG_CASE );
// [0 => 'C', 1 => 'b'] because 'C' -> 'c' and 'c' > 'b'

asort()

Sorts all elements and maintains the key association.

public function asort( int $options = SORT_REGULAR ) : self

• @param int $options Sort options for asort()
• @return self Updated map for fluid interface

The keys are preserved using this method and no new map is created.

The parameter modifies how the values are compared. Possible parameter values are:

• SORT_REGULAR : compare elements normally (don't change types)
• SORT_NUMERIC : compare elements numerically
• SORT_STRING : compare elements as strings
• SORT_LOCALE_STRING : compare elements as strings, based on the current locale or changed by setlocale()
• SORT_NATURAL : compare elements as strings using "natural ordering" like natsort()
• SORT_FLAG_CASE : use SORT_STRING|SORT_FLAG_CASE and SORT_NATURAL|SORT_FLAG_CASE to sort strings case-insensitively

Examples:

Map::from( ['a' => 1, 'b' => 0] )->asort();
// ['b' => 0, 'a' => 1]

Map::from( [0 => 'b', 1 => 'a'] )->asort();
// [1 => 'a', 0 => 'b']

Map::from( [0 => 'C', 1 => 'b'] )->asort();
// [0 => 'C', 1 => 'b'] because 'C' < 'b'

Map::from( [0 => 'C', 1 => 'b'] )->arsort( SORT_STRING|SORT_FLAG_CASE );
// [1 => 'b', 0 => 'C'] because 'C' -> 'c' and 'c' > 'b'

before()

Returns the elements before the given one.

public function before( $value ) : self

• @param mixed $value Value or function with (item, key) parameters
• @return self New map with the elements before the given one

The keys are preserved using this method.

Examples:

Map::from( ['a' => 1, 'b' => 0] )->before( 0 );
// ['a' => 1]

Map::from( [0 => 'b', 1 => 'a'] )->before( 'a' );
// [0 => 'b']

Map::from( ['a', 'c', 'b'] )->before( function( $item, $key ) {
    return $key >= 1;
} );
// [0 => 'a']

call()

Calls the given method on all items and returns the result.

public function call( string $name, array $params = [] ) : self

• @param string $name Method name
• @param array $params List of parameters
• @return self Map with results from all elements

This method can call methods on the map entries that are also implemented by the map object itself and are therefore not reachable when using the magic __call() method. If some entries are not objects, they will be skipped.

The keys from the original map are preserved in the returned in the new map.

Examples:

$item = new MyClass( ['myprop' => 'val'] ); // implements methods get() and toArray()

Map::from( [$item, $item] )->call( 'get', ['myprop'] );
// ['val', 'val']

Map::from( [$item, $item] )->call( 'toArray' );
// [['myprop' => 'val'], ['myprop' => 'val']]

chunk()

Chunks the map into arrays with the given number of elements.

public function chunk( int $size, bool $preserve = false ) : self

• @param int $size Maximum size of the sub-arrays
• @param bool $preserve Preserve keys in new map
• @return self New map with elements chunked in sub-arrays
• @throws \InvalidArgumentException If size is smaller than 1

The last chunk may contain less elements than the given number.

The sub-arrays of the returned map are plain PHP arrays. If you need Map objects, then wrap them with Map::from() when you iterate over the map.

Examples:

Map::from( [0, 1, 2, 3, 4] )->chunk( 3 );
// [[0, 1, 2], [3, 4]]

Map::from( ['a' => 0, 'b' => 1, 'c' => 2] )->chunk( 2 );
// [['a' => 0, 'b' => 1], ['c' => 2]]

clear()

Removes all elements from the current map.

public function clear() : self

• @return self Same map for fluid interface

Examples:

Map::from( [0, 1] )->clear();
// internal : []

col()

Returns the values of a single column/property from an array of arrays or list of elements in a new map.

public function col( string $valuecol = null, string $indexcol = null ) : self

• @param string|null $valuecol Name or path of the value property
• @param string|null $indexcol Name or path of the index property
• @return self New instance with mapped entries

If $indexcol is omitted, it's value is NULL or not set, the result will be indexed from 0-n. Items with the same value for $indexcol will overwrite previous items and only the last one will be part of the resulting map.

This does also work to map values from multi-dimensional arrays by passing the keys of the arrays separated by the delimiter ("/" by default), e.g. key1/key2/key3 to get val from ['key1' => ['key2' => ['key3' => 'val']]]. The same applies to public properties of objects or objects implementing __isset() and __get() methods.

Examples:

Map::from( [['id' => 'i1', 'val' => 'v1'], ['id' => 'i2', 'val' => 'v2']] )->col( 'val' );
// ['v1', 'v2']

Map::from( [['id' => 'i1', 'val' => 'v1'], ['id' => 'i2', 'val' => 'v2']] )->col( 'val', 'id' );
// ['i1' => 'v1', 'i2' => 'v2']

Map::from( [['id' => 'i1', 'val' => 'v1'], ['id' => 'i2', 'val' => 'v2']] )->col( null, 'id' );
// ['i1' => ['id' => 'i1', 'val' => 'v1'], 'i2' => ['id' => 'i2', 'val' => 'v2']]

Map::from( [['id' => 'ix', 'val' => 'v1'], ['id' => 'ix', 'val' => 'v2']] )->col( null, 'id' );
// ['ix' => ['id' => 'ix', 'val' => 'v2']]

Map::from( [['foo' => ['bar' => 'one', 'baz' => 'two']]] )->col( 'foo/baz', 'foo/bar' );
// ['one' => 'two']

Map::from( [['foo' => ['bar' => 'one']]] )->col( 'foo/baz', 'foo/bar' );
// ['one' => null]

Map::from( [['foo' => ['baz' => 'two']]] )->col( 'foo/baz', 'foo/bar' );
// ['two']

collapse()

Collapses all sub-array elements recursively to a new map.

public function collapse( int $depth = null ) : self

• @param int|null $depth Number of levels to collapse for multi-dimensional arrays or NULL for all
• @return self New map with all sub-array elements added into it recursively, up to the specified depth

The keys are preserved and already existing elements will be overwritten. This is also true for numeric keys! This method is similar than flat() but replaces already existing elements.

A value smaller than 1 for depth will return the same map elements. Collapsing does also work if elements implement the "Traversable" interface (which the Map object does).

Examples:

Map::from( [0 => ['a' => 0, 'b' => 1], 1 => ['c' => 2, 'd' => 3]] )->collapse();
// ['a' => 0, 'b' => 1, 'c' => 2, 'd' => 3]

Map::from( [0 => ['a' => 0, 'b' => 1], 1 => ['a' => 2]] )->collapse();
// ['a' => 2, 'b' => 1]

Map::from( [0 => [0 => 0, 1 => 1], 1 => [0 => ['a' => 2, 0 => 3], 1 => 4]] )->collapse();
// [0 => 3, 1 => 4, 'a' => 2]

Map::from( [0 => [0 => 0, 'a' => 1], 1 => [0 => ['b' => 2, 0 => 3], 1 => 4]] )->collapse( 1 );
// [0 => ['b' => 2, 0 => 3], 1 => 4, 'a' => 1]

Map::from( [0 => [0 => 0, 'a' => 1], 1 => Map::from( [0 => ['b' => 2, 0 => 3], 1 => 4] )] )->collapse();
// [0 => 3, 'a' => 1, 'b' => 2, 1 => 4]

concat()

Pushs all of the given elements onto the map without creating a new map.

public function concat( iterable $elements ) : self

• @param iterable $elements List of elements
• @return self Updated map for fluid interface

Examples:

Map::from( ['foo'] )->concat( ['bar'] );
// ['foo', 'bar']

Map::from( ['foo'] )->concat( new Map( ['bar' => 'baz'] ) );
// ['foo', 'baz']

combine()

Combines the values of the map as keys with the passed elements as values.

public function combine( iterable $values ) : self

• @param iterable $values Values of the new map
• @return self New map

Examples:

Map::from( ['name', 'age'] )->combine( ['Tom', 29] );
// ['name' => 'Tom', 'age' => 29]

copy()

Creates a new map with the same elements.

public function copy() : self

• @return self New map

Both maps share the same array until one of the map objects modifies the array. Then, the array is copied and the copy is modfied (copy on write).

Examples:

$m = Map::from( ['foo', 'bar'] );

$m2 = $m->copy();
// internal: ['foo', 'bar'] both two maps

count()

Counts the number of elements in the map.

public function count() : int

• @return int Number of elements

Examples:

Map::from( ['foo', 'bar'] )->count();
// 2

countBy()

Counts how often the same values are in the map.

public function countBy( callable $callback = null ) : self

• @param callable|null $callback Function with (value, key) parameters which returns the value to use for counting
• @return self New map with values as keys and their count as value

Examples:

Map::from( [1, 'foo', 2, 'foo', 1] )->countBy();
// [1 => 2, 'foo' => 2, 2 => 1]

Map::from( [1.11, 3.33, 3.33, 9.99] )->countBy();
// ['1.11' => 1, '3.33' => 2, '9.99' => 1]

Map::from( ['[email protected]', '[email protected]', '[email protected]'] )->countBy( function( $email ) {
    return substr( strrchr( $email, '@' ), 1 );
} );
// ['gmail.com' => 2, 'yahoo.com' => 1]

dd()

Dumps the map content and terminates the script.

public function dd( callable $callback = null ) : self

• @param callable|null $callback Function receiving the map elements as parameter (optional)

The dd() method is very helpful to see what are the map elements passed between two map methods in a method call chain. It stops execution of the script afterwards to avoid further output.

Examples:

Map::from( ['a' => 'foo', 'b' => 'bar'] )->sort()->dd()->first();
/*
Array
(
    [0] => bar
    [1] => foo
)
*/

The first() method isn't executed at all.

delimiter()

Sets or returns the seperator for paths to values in multi-dimensional arrays or objects.

public static function delimiter( ?string $char = null ) : string

• @param string $char Separator character, e.g. "." for "key.to.value" instaed of "key/to/value"
• @return string Separator used up to now

The static method only changes the separator for new maps created afterwards. Already existing maps will continue to use the previous separator. To change the separator of an existing map, use the sep() method instead.

Examples:

Map::delimiter( '.' );
// '/'

Map::from( ['foo' => ['bar' => 'baz']] )->get( 'foo.bar' );
// 'baz'

diff()

Returns the keys/values in the map whose values are not present in the passed elements in a new map.

public function diff( iterable $elements, callable $callback = null ) : self

• @param iterable $elements List of elements
• @param callable|null $callback Function with (valueA, valueB) parameters and returns -1 (<), 0 (=) and 1 (>)
• @return self New map

Examples:

Map::from( ['a' => 'foo', 'b' => 'bar'] )->diff( ['bar'] );
// ['a' => 'foo']

If a callback is passed, the given function will be used to compare the values. The function must accept two parameters (value A and B) and must return -1 if value A is smaller than value B, 0 if both are equal and 1 if value A is greater than value B. Both, a method name and an anonymous function can be passed:

Map::from( [0 => 'a'] )->diff( [0 => 'A'], 'strcasecmp' );
// []

Map::from( ['b' => 'a'] )->diff( ['B' => 'A'], 'strcasecmp' );
// []

Map::from( ['b' => 'a'] )->diff( ['c' => 'A'], function( $valA, $valB ) {
    return strtolower( $valA ) <=> strtolower( $valB );
} );
// []

All examples will return an empty map because both contain the same values when compared case insensitive.

diffAssoc()

Returns the keys/values in the map whose keys and values are not present in the passed elements in a new map.

public function diffAssoc( iterable $elements, callable $callback = null ) : self

• @param iterable $elements List of elements
• @param callable|null $callback Function with (valueA, valueB) parameters and returns -1 (<), 0 (=) and 1 (>)
• @return self New map

Examples:

Map::from( ['a' => 'foo', 'b' => 'bar'] )->diffAssoc( new Map( ['foo', 'b' => 'bar'] ) );
// ['a' => 'foo']

If a callback is passed, the given function will be used to compare the values. The function must accept two parameters (valA, valB) and must return -1 if value A is smaller than value B, 0 if both are equal and 1 if value A is greater than value B. Both, a method name and an anonymous function can be passed:

Map::from( [0 => 'a'] )->diffAssoc( [0 => 'A'], 'strcasecmp' );
// []

Map::from( ['b' => 'a'] )->diffAssoc( ['B' => 'A'], 'strcasecmp' );
// []

Map::from( ['b' => 'a'] )->diffAssoc( ['c' => 'A'], function( $valA, $valB ) {
    return strtolower( $valA ) <=> strtolower( $valB );
} );
// ['b' => 'a']

The first and second example will return an empty map because both contain the same values when compared case insensitive. In the third example, the keys doesn't match ("b" vs. "c").

diffKeys()

Returns the key/value pairs from the map whose keys are not present in the passed elements in a new map.

public function diffKeys( iterable $elements, callable $callback = null ) : self

• @param iterable $elements List of elements
• @param callable|null $callback Function with (keyA, keyB) parameters and returns -1 (<), 0 (=) and 1 (>)
• @return self New map

Examples:

Map::from( ['a' => 'foo', 'b' => 'bar'] )->diffKeys( new Map( ['foo', 'b' => 'baz'] ) );
// ['a' => 'foo']

If a callback is passed, the given function will be used to compare the keys. The function must accept two parameters (key A and B) and must return -1 if key A is smaller than key B, 0 if both are equal and 1 if key A is greater than key B. Both, a method name and an anonymous function can be passed:

Map::from( [0 => 'a'] )->diffKeys( [0 => 'A'], 'strcasecmp' );
// []

Map::from( ['b' => 'a'] )->diffKeys( ['B' => 'X'], 'strcasecmp' );
// []

Map::from( ['b' => 'a'] )->diffKeys( ['c' => 'a'], function( $keyA, $keyB ) {
    return strtolower( $keyA ) <=> strtolower( $keyB );
} );
// ['b' => 'a']

The first and second example will return an empty map because both contain the same keys when compared case insensitive. The third example will return ['b' => 'a'] because the keys doesn't match ("b" vs. "c").

dump()

Dumps the map content using the given function (print_r by default).

public function dump( callable $callback = null ) : self

• @param callable|null $callback Function receiving the map elements as parameter (optional)
• @return self Same map for fluid interface

The dump() method is very helpful to see what are the map elements passed between two map methods in a method call chain.

Examples:

Map::from( ['a' => 'foo', 'b' => 'bar'] )->dump()->asort()->dump( 'var_dump' );
/*
Array
(
    [a] => foo
    [b] => bar
)

array(1) {
  ["b"]=>
  string(3) "bar"
  ["a"]=>
  string(3) "foo"
}
*/

duplicates()

Returns the duplicate values from the map.

public function duplicates( string $col = null ) : self

• @param string|null $col Key of the nested array or object to check for
• @return self New map

This does also work to map values from multi-dimensional arrays by passing the keys of the arrays separated by the delimiter ("/" by default), e.g. key1/key2/key3 to get val from ['key1' => ['key2' => ['key3' => 'val']]]. The same applies to public properties of objects or objects implementing __isset() and __get() methods.

The keys in the result map are preserved.

Examples:

Map::from( [1, 2, '1', 3] )->duplicates()
// [2 => '1']

Map::from( [['p' => '1'], ['p' => 1], ['p' => 2]] )->duplicates( 'p' )
// [1 => ['p' => 1]]

Map::from( [['i' => ['p' => '1']], ['i' => ['p' => 1]]] )->duplicates( 'i/p' )
// [1 => ['i' => ['p' => '1']]]

each()

Executes a callback over each entry until FALSE is returned.

public function each( \Closure $callback ) : self

• @param \Closure $callback Function with (value, key) parameters and returns TRUE/FALSE
• @return self Same map for fluid interface

Examples:

$result = [];
Map::from( [0 => 'a', 1 => 'b'] )->each( function( $value, $key ) use ( &$result ) {
    $result[$key] = strtoupper( $value );
    return false;
} );
// $result = [0 => 'A']

The $result array will contain [0 => 'A'] because FALSE is returned after the first entry and all other entries are then skipped.

empty()

Determines if the map is empty or not.

public function empty() : bool

• @return bool TRUE if map is empty, FALSE if not

The method is equivalent to isEmpty().

Examples:

Map::from( [] )->empty();
// true

Map::from( ['a'] )->empty();
// false

equals()

Tests if the passed elements are equal to the elements in the map.

public function equals( iterable $elements ) : bool

• @param iterable $elements List of elements to test against
• @return bool TRUE if both are equal, FALSE if not

The method differs to is() in the fact that it doesn't care about the keys by default. The elements are only loosely compared and the keys are ignored.

Values are compared by their string values:

(string) $item1 === (string) $item2

Examples:

Map::from( ['a'] )->equals( ['a', 'b'] );
// false

Map::from( ['a', 'b'] )->equals( ['b'] );
// false

Map::from( ['a', 'b'] )->equals( ['b', 'a'] );
// true

every()

Verifies that all elements pass the test of the given callback.

public function every( \Closure $callback ) : bool

• @param \Closure $callback Function with (value, key) parameters and returns TRUE/FALSE
• @return bool True if all elements pass the test, false if if fails for at least one element

Examples:

Map::from( [0 => 'a', 1 => 'b'] )->every( function( $value, $key ) {
    return is_string( $value );
} );
// true

Map::from( [0 => 'a', 1 => 100] )->every( function( $value, $key ) {
    return is_string( $value );
} );
// false

except()

Returns a new map without the passed element keys.

public function except( $keys ) : self

• @param mixed|array $keys List of keys to remove
• @return self New map

Examples:

Map::from( ['a' => 1, 'b' => 2, 'c' => 3] )->except( 'b' );
// ['a' => 1, 'c' => 3]

Map::from( [1 => 'a', 2 => 'b', 3 => 'c'] )->except( [1, 3] );
// [2 => 'b']

explode()

Creates a new map with the string splitted by the delimiter.

public static function explode( string $delimiter , string $string , int $limit = PHP_INT_MAX ) : self

• @param string $delimiter Delimiter character, string or empty string
• @param string $string String to split
• @param int $limit Maximum number of element with the last element containing the rest of the string
• @return self New map with splitted parts

A limit of "0" is treated the same as "1". If limit is negative, the rest of the string is dropped and not part of the returned map.

Examples:

Map::explode( ',', 'a,b,c' );
// ['a', 'b', 'c']

Map::explode( '<-->', 'a a<-->b b<-->c c' );
// ['a a', 'b b', 'c c']

Map::explode( '', 'string' );
// ['s', 't', 'r', 'i', 'n', 'g']

Map::explode( '|', 'a|b|c', 2 );
// ['a', 'b|c']

Map::explode( '', 'string', 2 );
// ['s', 't', 'ring']

Map::explode( '|', 'a|b|c|d', -2 );
// ['a', 'b']

Map::explode( '', 'string', -3 );
// ['s', 't', 'r']

filter()

Runs a filter over each element of the map and returns a new map.

public function filter( callable $callback = null ) : self

• @param callable|null $callback Function with (item) parameter and returns TRUE/FALSE
• @return self New map

If no callback is passed, all values which are empty, null or false will be removed if their value converted to boolean is FALSE:

(bool) $value === false

Examples:

Map::from( [2 => 'a', 6 => 'b', 13 => 'm', 30 => 'z'] )->filter( function( $value, $key ) {
    return $key < 10 && $value < 'n';
} );
// ['a', 'b']

find()

Returns the first matching element where the callback returns TRUE.

public function find( \Closure $callback, $default = null, bool $reverse = false )

• @param \Closure $callback Function with (value, key) parameters and returns TRUE/FALSE
• @param mixed $default Default value or exception if the map contains no elements
• @param bool $reverse TRUE to test elements from back to front, FALSE for front to back (default)
• @return mixed|null First matching value, passed default value or an exception

Examples:

Map::from( ['a', 'c', 'e'] )->find( function( $value, $key ) {
    return $value >= 'b';
} );
// 'c'

Map::from( ['a', 'c', 'e'] )->find( function( $value, $key ) {
    return $value >= 'b';
}, null, true );
// 'e' because $reverse = true

Map::from( [] )->find( function( $value, $key ) {
    return $value >= 'b';
}, 'none' );
// 'none'

Map::from( [] )->find( function( $value, $key ) {
    return $value >= 'b';
}, new \Exception( 'error' ) );
// throws \Exception

first()

Returns the first element from the map.

public function first( $default = null )

• @param mixed $default Default value or exception if the map contains no elements
• @return mixed First value of map, (generated) default value or an exception

Examples:

Map::from( ['a', 'b'] )->first();
// 'a'

Map::from( [] )->first( 'x' );
// 'x'

Map::from( [] )->first( new \Exception( 'error' ) );
// throws \Exception

Map::from( [] )->first( function() { return rand(); } );
// random integer

firstKey()

Returns the first key from the map.

public function firstKey()

• @return mixed First key of map or NULL if empty

Examples:

Map::from( ['a' => 1, 'b' => 2] )->lastKey();
// 'a'

Map::from( [] )->lastKey();
// null

flat()

Creates a new map with all sub-array elements added recursively

public function flat( int $depth = null ) : self

• @param int|null $depth Number of levels to flatten multi-dimensional arrays
• @return self New map with all sub-array elements added into it recursively, up to the specified depth

The keys are not preserved and the new map elements will be numbered from 0-n. A value smaller than 1 for depth will return the same map elements indexed from 0-n. Flattening does also work if elements implement the "Traversable" interface (which the Map object does).

This method is similar than collapse() but doesn't replace existing elements.

Examples:

Map::from( [[0, 1], [2, 3]] )->flat();
// [0, 1, 2, 3]

Map::from( [[0, 1], [[2, 3], 4]] )->flat();
// [0, 1, 2, 3, 4]

Map::from( [[0, 1], [[2, 3], 4]] )->flat( 1 );
// [0, 1, [2, 3], 4]

Map::from( [[0, 1], Map::from( [[2, 3], 4] )] )->flat();
// [0, 1, 2, 3, 4]

flip()

Exchanges the keys with their values and vice versa.

public function flip() : self

• @return self New map with keys as values and values as keys

Examples:

Map::from( ['a' => 'X', 'b' => 'Y'] )->flip();
// ['X' => 'a', 'Y' => 'b']

from()

Creates a new map instance if the value isn't one already.

public static function from( $elements = [] ) : self

• @param mixed $elements List of elements or single value
• @return self New map

Examples:

Map::from( [] );
// internal: []

Map::from( null );
// internal: []

Map::from( 'a' );
// internal: ['a']

Map::from( new Map() );
// internal: []

Map::from( new ArrayObject() );
// internal: []

fromJson()

Creates a new map instance from a JSON string.

public static function fromJson( string $json, int $options = JSON_BIGINT_AS_STRING ) : self

• @param int $options Combination of JSON_* constants
• @return self Map from decoded JSON string

There are several options available for decoding the JSON string which are described in the PHP json_decode() manual. The parameter can be a single JSON_* constant or a bitmask of several constants combine by bitwise OR (|), e.g.:

JSON_BIGINT_AS_STRING|JSON_INVALID_UTF8_IGNORE

Examples:

Map::fromJson( '["a", "b"]' );
// ['a', 'b']

Map::fromJson( '{"a": "b"}' );
// ['a' => 'b']

Map::fromJson( '""' );
['']

get()

Returns an element from the map by key.

public function get( $key, $default = null )

• @param mixed $key Key or path to the requested item
• @param mixed $default Default value if no element matches
• @return mixed Value from map or default value

This does also work to map values from multi-dimensional arrays by passing the keys of the arrays separated by the delimiter ("/" by default), e.g. key1/key2/key3 to get val from ['key1' => ['key2' => ['key3' => 'val']]]. The same applies to public properties of objects or objects implementing __isset() and __get() methods.

Examples:

Map::from( ['a' => 'X', 'b' => 'Y'] )->get( 'a' );
// 'X'

Map::from( ['a' => 'X', 'b' => 'Y'] )->get( 'c', 'Z' );
// 'Z'

Map::from( ['a' => ['b' => ['c' => 'Y']]] )->get( 'a/b/c' );
// 'Y'

Map::from( [] )->get( new \Exception( 'error' ) );
// throws \Exception

Map::from( [] )->get( function() { return rand(); } );
// random integer

getIterator()

Returns an iterator for the elements.

public function getIterator() : \Iterator

• @return \Iterator Over map elements

This method will be used by e.g. foreach() to loop over all entries.

Examples:

foreach( Map::from( ['a', 'b'] ) as $value ) {
    // ...
}

groupBy()

Groups associative array elements or objects by the passed key or closure.

public function groupBy( $key ) : self

• @param \Closure|string $key Closure function with (item, idx) parameters returning the key or the key itself to group by
• @return self New map with elements grouped by the given key

Instead of overwriting items with the same keys like to the col() method does, groupBy() keeps all entries in sub-arrays. It's preserves the keys of the orignal map entries too.

Examples:

$list = [
    10 => ['aid' => 123, 'code' => 'x-abc'],
    20 => ['aid' => 123, 'code' => 'x-def'],
    30 => ['aid' => 456, 'code' => 'x-def']
];

Map::from( $list )->groupBy( 'aid' );
/*
[
    123 => [
        10 => ['aid' => 123, 'code' => 'x-abc'],
        20 => ['aid' => 123, 'code' => 'x-def']
    ],
    456 => [
        30 => ['aid' => 456, 'code' => 'x-def']
    ]
]
*/

Map::from( $list )->groupBy( function( $item, $key ) {
    return substr( $item['code'], -3 );
} );
/*
[
    'abc' => [
        10 => ['aid' => 123, 'code' => 'x-abc']
    ],
    'def' => [
        20 => ['aid' => 123, 'code' => 'x-def'],
        30 => ['aid' => 456, 'code' => 'x-def']
    ]
]
*/

In case the passed key doesn't exist in one or more items, these items are stored in a sub-array using an empty string as key:

$list = [
    10 => ['aid' => 123, 'code' => 'x-abc'],
    20 => ['aid' => 123, 'code' => 'x-def'],
    30 => ['aid' => 456, 'code' => 'x-def']
];

Map::from( $list )->groupBy( 'xid' );
/*
[
    '' => [
        10 => ['aid' => 123, 'code' => 'x-abc'],
        20 => ['aid' => 123, 'code' => 'x-def'],
        30 => ['aid' => 456, 'code' => 'x-def']
    ]
]
*/

has()

Determines if a key or several keys exists in the map.

public function has( $key ) : bool

• @param mixed|array $key Key or path to the requested item
• @return bool TRUE if key is available in map, FALSE if not

If several keys are passed as array, all keys must exist in the map to return TRUE.

This does also work to map values from multi-dimensional arrays by passing the keys of the arrays separated by the delimiter ("/" by default), e.g. key1/key2/key3 to get val from ['key1' => ['key2' => ['key3' => 'val']]]. The same applies to public properties of objects or objects implementing __isset() and __get() methods.

Examples:

Map::from( ['a' => 'X', 'b' => 'Y'] )->has( 'a' );
// true

Map::from( ['a' => 'X', 'b' => 'Y'] )->has( ['a', 'b'] );
// false

Map::from( ['a' => ['b' => ['c' => 'Y']]] )->has( 'a/b/c' );
// true

Map::from( ['a' => 'X', 'b' => 'Y'] )->has( 'c' );
// false

Map::from( ['a' => 'X', 'b' => 'Y'] )->has( ['a', 'c'] );
// false

Map::from( ['a' => 'X', 'b' => 'Y'] )->has( 'X' );
// false

in()

Tests if the passed element or elements are part of the map.

public function in( $element, bool $strict = false ) : bool

• @param mixed|array $element Element or elements to search for in the map
• @param bool $strict TRUE to check the type too, using FALSE '1' and 1 will be the same
• @return bool TRUE if all elements are available in map, FALSE if not

Examples:

Map::from( ['a', 'b'] )->in( 'a' );
// true

Map::from( ['a', 'b'] )->in( ['a', 'b'] );
// true

Map::from( ['a', 'b'] )->in( 'x' );
// false

Map::from( ['a', 'b'] )->in( ['a', 'x'] );
// false

Map::from( ['1', '2'] )->in( 2, true );
// false

includes()

Tests if the passed element or elements are part of the map.

public function includes( $element, bool $strict = false ) : bool

• @param mixed|array $element Element or elements to search for in the map
• @param bool $strict TRUE to check the type too, using FALSE '1' and 1 will be the same
• @return bool TRUE if all elements are available in map, FALSE if not

This method is an alias for in(). For performance reasons, in() should be preferred because it uses one method call less than includes().

Examples:

Map::from( ['a', 'b'] )->includes( 'a' );
// true

Map::from( ['a', 'b'] )->includes( ['a', 'b'] );
// true

Map::from( ['a', 'b'] )->includes( 'x' );
// false

Map::from( ['a', 'b'] )->includes( ['a', 'x'] );
// false

Map::from( ['1', '2'] )->includes( 2, true );
// false

intersect()

Returns all values in a new map that are available in both, the map and the given elements.

public function intersect( iterable $elements, callable $callback = null ) : self

• @param iterable $elements List of elements
• @param callable|null $callback Function with (valueA, valueB) parameters and returns -1 (<), 0 (=) and 1 (>)
• @return self New map

Examples:

Map::from( ['a' => 'foo', 'b' => 'bar'] )->intersect( ['bar'] );
// ['b' => 'bar']

If a callback is passed, the given function will be used to compare the values. The function must accept two parameters (vaA, valB) and must return -1 if value A is smaller than value B, 0 if both are equal and 1 if value A is greater than value B. Both, a method name and an anonymous function can be passed:

Map::from( [0 => 'a'] )->intersect( [0 => 'A'], 'strcasecmp' );
// ['a']

Map::from( ['b' => 'a'] )->intersect( ['B' => 'A'], 'strcasecmp' );
// ['a']

Map::from( ['b' => 'a'] )->intersect( ['c' => 'A'], function( $valA, $valB ) {
    return strtolower( $valA ) <=> strtolower( $valB );
} );
// ['a']

intersectAssoc()

Returns all values in a new map that are available in both, the map and the given elements while comparing the keys too.

public function intersectAssoc( iterable $elements, callable $callback = null ) : self

• @param iterable $elements List of elements
• @param callable|null $callback Function with (valueA, valueB) parameters and returns -1 (<), 0 (=) and 1 (>)
• @return self New map

Examples:

Map::from( ['a' => 'foo', 'b' => 'bar'] )->intersectAssoc( new Map( ['foo', 'b' => 'bar'] ) );
// ['a' => 'foo']

If a callback is passed, the given function will be used to compare the values. The function must accept two parameters (valA, valB) and must return -1 if value A is smaller than value B, 0 if both are equal and 1 if value A is greater than value B. Both, a method name and an anonymous function can be passed:

Map::from( [0 => 'a'] )->intersectAssoc( [0 => 'A'], 'strcasecmp' );
// [0 => 'a']

Map::from( ['b' => 'a'] )->intersectAssoc( ['B' => 'A'], 'strcasecmp' );
// ['b' => 'a']

Map::from( ['b' => 'a'] )->intersectAssoc( ['c' => 'A'], function( $valA, $valB ) {
    return strtolower( $valA ) <=> strtolower( $valB );
} );
// []

intersectKeys()

Returns all values in a new map that are available in both, the map and the given elements by comparing the keys only.

public function intersectKeys( iterable $elements, callable $callback = null ) : self

• @param iterable $elements List of elements
• @param callable|null $callback Function with (keyA, keyB) parameters and returns -1 (<), 0 (=) and 1 (>)
• @return self New map

Examples:

Map::from( ['a' => 'foo', 'b' => 'bar'] )->intersectKeys( new Map( ['foo', 'b' => 'baz'] ) );
// ['b' => 'bar']

If a callback is passed, the given function will be used to compare the keys. The function must accept two parameters (key A and B) and must return -1 if key A is smaller than key B, 0 if both are equal and 1 if key A is greater than key B. Both, a method name and an anonymous function can be passed:

Map::from( [0 => 'a'] )->intersectKeys( [0 => 'A'], 'strcasecmp' );
// [0 => 'a']

Map::from( ['b' => 'a'] )->intersectKeys( ['B' => 'X'], 'strcasecmp' );
// ['b' => 'a']

Map::from( ['b' => 'a'] )->intersectKeys( ['c' => 'a'], function( $keyA, $keyB ) {
    return strtolower( $keyA ) <=> strtolower( $keyB );
} );
// []

is()

Tests if the map consists of the same keys and values

public function is( iterable $list, bool $strict = false ) : bool

• @param iterable $list List of key/value pairs to compare with
• @param bool $strict TRUE for comparing order of elements too, FALSE for key/values only
• @param bool TRUE if given list is equal, FALSE if not

Examples:

Map::from( ['a', 'b'] )->is( ['b', 'a'] );
// true

Map::from( ['a', 'b'] )->is( ['b', 'a'], true );
// false

Map::from( [1, 2] )->is( ['1', '2'] );
// false

isEmpty()

Determines if the map is empty or not.

public function isEmpty() : bool

• @return bool TRUE if map is empty, FALSE if not

The method is equivalent to empty().

Examples:

Map::from( [] )->isEmpty();
// true

Map::from( ['a'] )-isEmpty();
// false

join()

Concatenates the string representation of all elements.

public function join( $glue = '' ) : string

• @param string $glue Character or string added between elements
• @return string String of concatenated map elements

Objects that implement __toString() does also work, otherwise (and in case of arrays) a PHP notice is generated. NULL and FALSE values are treated as empty strings.

Examples:

Map::from( ['a', 'b', false] )->join();
// 'ab'

Map::from( ['a', 'b', null, false] )->join( '-' );
// 'a-b--'

keys()

Returns the keys of the map elements in a new map object.

public function keys() : self

• @return self New map

Examples:

Map::from( ['a', 'b'] );
// [0, 1]

Map::from( ['a' => 0, 'b' => 1] );
// ['a', 'b']

krsort()

Sorts the elements by their keys in reverse order.

public function krsort( int $options = SORT_REGULAR ) : self

• @param int $options Sort options for krsort()
• @return self Updated map for fluid interface

The parameter modifies how the keys are compared. Possible values are:

• SORT_REGULAR : compare elements normally (don't change types)
• SORT_NUMERIC : compare elements numerically
• SORT_STRING : compare elements as strings
• SORT_LOCALE_STRING : compare elements as strings, based on the current locale or changed by setlocale()
• SORT_NATURAL : compare elements as strings using "natural ordering" like natsort()
• SORT_FLAG_CASE : use SORT_STRING|SORT_FLAG_CASE and SORT_NATURAL|SORT_FLAG_CASE to sort strings case-insensitively

The keys are preserved using this method and no new map is created.

Examples:

Map::from( ['b' => 0, 'a' => 1] )->krsort();
// ['a' => 1, 'b' => 0]

Map::from( [1 => 'a', 0 => 'b'] )->krsort();
// [0 => 'b', 1 => 'a']

ksort()

Sorts the elements by their keys.

public function ksort( int $options = SORT_REGULAR ) : self

• @param int $options Sort options for ksort()
• @return self Updated map for fluid interface

The parameter modifies how the keys are compared. Possible values are:

• SORT_REGULAR : compare elements normally (don't change types)
• SORT_NUMERIC : compare elements numerically
• SORT_STRING : compare elements as strings
• SORT_LOCALE_STRING : compare elements as strings, based on the current locale or changed by setlocale()
• SORT_NATURAL : compare elements as strings using "natural ordering" like natsort()
• SORT_FLAG_CASE : use SORT_STRING|SORT_FLAG_CASE and SORT_NATURAL|SORT_FLAG_CASE to sort strings case-insensitively

The keys are preserved using this method and no new map is created.

Examples:

Map::from( ['b' => 0, 'a' => 1] )->ksort();
// ['a' => 1, 'b' => 0]

Map::from( [1 => 'a', 0 => 'b'] )->ksort();
// [0 => 'b', 1 => 'a']

last()

Returns the last element from the map.

public function last( $default = null )

• @param mixed $default Default value or exception if the map contains no elements
• @return mixed Last value of map, (generated) default value or an exception

Examples:

Map::from( ['a', 'b'] )->last();
// 'b'

Map::from( [] )->last( 'x' );
// 'x'

Map::from( [] )->last( new \Exception( 'error' ) );
// throws \Exception

Map::from( [] )->last( function() { return rand(); } );
// random integer

lastKey()

Returns the last key from the map.

public function lastKey()

• @return mixed Last key of map or NULL if empty

Examples:

Map::from( ['a' => 1, 'b' => 2] )->lastKey();
// 'b'

Map::from( [] )->lastKey();
// null

map()

Calls the passed function once for each element and returns a new map for the result.

public function map( callable $callback ) : self

• @param callable $callback Function with (value, key) parameters and returns computed result
• @return self New map with the original keys and the computed values

Examples:

Map::from( ['a' => 2, 'b' => 4] )->map( function( $value, $key ) {
    return $value * 2;
} );
// ['a' => 4, 'b' => 8]

max()

Returns the maximum value of all elements.

public function max( string $col = null )

• @param string|null $col Key in the nested array or object to check for
• @return mixed Maximum value or NULL if there are no elements in the map

This does also work to map values from multi-dimensional arrays by passing the keys of the arrays separated by the delimiter ("/" by default), e.g. key1/key2/key3 to get val from ['key1' => ['key2' => ['key3' => 'val']]]. The same applies to public properties of objects or objects implementing __isset() and __get() methods.

Be careful comparing elements of different types because this can have unpredictable results due to the PHP comparison rules

Examples:

Map::from( [1, 3, 2, 5, 4] )->max();
// 5

Map::from( ['bar', 'foo', 'baz'] )->max();
// 'foo'

Map::from( [['p' => 30], ['p' => 50], ['p' => 10]] )->max( 'p' );
// 50

Map::from( [['i' => ['p' => 30]], ['i' => ['p' => 50]]] )->max( 'i/p' );
// 50

merge()

Merges the map with the given elements without returning a new map.

public function merge( iterable $elements, bool $recursive = false ) : self

• @param iterable $elements List of elements
• @param bool $recursive TRUE to merge nested arrays too, FALSE for first level elements only
• @return self Updated map for fluid interface

Elements with the same non-numeric keys will be overwritten, elements with the same numeric keys will be added.

The method is similar to replace() but doesn't replace elements with the same numeric keys. If you want to be sure that all passed elements are added without replacing existing ones, use concat() instead.

Examples:

Map::from( ['a', 'b'] )->merge( ['b', 'c'] );
// ['a', 'b', 'b', 'c']

Map::from( ['a' => 1, 'b' => 2] )->merge( ['b' => 4, 'c' => 6] );
// ['a' => 1, 'b' => 4, 'c' => 6]

Map::from( ['a' => 1, 'b' => 2] )->merge( ['b' => 4, 'c' => 6], true );
// ['a' => 1, 'b' => [2, 4], 'c' => 6]

method()

Registers a custom method that has access to the class properties if called non-static.

public static function method( string $name, \Closure $function )

• @param string $name Method name
• @param \Closure $function Anonymous method

Examples:

Map::method( 'foo', function( $arg1, $arg2 ) {
    return array_merge( $this->elements, [$arg1, $arg2] );
} );

(Map::from( ['bar'] ))->foo( 'foo', 'baz' );
// ['bar', 'foo', 'baz']

Map::foo( 'foo', 'baz' );
// error because `$this->elements` isn't available

Static calls can't access $this->elements but can operate on the parameter values:

Map::method( 'bar', function( $arg1, $arg2 ) {
    return new static( [$arg1, $arg2] );
} );

Map::foo( 'foo', 'baz' );
// ['foo', 'baz']

min()

Returns the minimum value of all elements.

public function min( string $col = null )

• @param string|null $col Key in the nested array or object to check for
• @return mixed Minimum value or NULL if there are no elements in the map

This does also work to map values from multi-dimensional arrays by passing the keys of the arrays separated by the delimiter ("/" by default), e.g. key1/key2/key3 to get val from ['key1' => ['key2' => ['key3' => 'val']]]. The same applies to public properties of objects or objects implementing __isset() and __get() methods.

Be careful comparing elements of different types because this can have unpredictable results due to the PHP comparison rules

Examples:

Map::from( [2, 3, 1, 5, 4] )->min();
// 1

Map::from( ['baz', 'foo', 'bar'] )->min();
// 'bar'

Map::from( [['p' => 30], ['p' => 50], ['p' => 10]] )->min( 'p' );
// 10

Map::from( [['i' => ['p' => 30]], ['i' => ['p' => 50]]] )->min( 'i/p' );
// 30

nth()

Returns every nth element from the map.

public function nth( int $step, int $offset = 0 ) : self

• @param int $step Step width
• @param int $offset Number of element to start from (0-based)
• @return self New map

Examples:

Map::from( ['a', 'b', 'c', 'd', 'e', 'f'] )->nth( 2 );
// ['a', 'c', 'e']

Map::from( ['a', 'b', 'c', 'd', 'e', 'f'] )->nth( 2, 1 );
// ['b', 'd', 'f']

offsetExists()

Determines if an element exists at an offset.

public function offsetExists( $key )

• @param mixed $key Key to check for
• @return bool TRUE if key exists, FALSE if not

Examples:

$map = Map::from( ['a' => 1, 'b' => 3, 'c' => null] );

isset( $map['b'] );
// true

isset( $map['c'] );
// false

isset( $map['d'] );
// false

offsetGet()

Returns an element at a given offset.

public function offsetGet( $key )

• @param mixed $key Key to return the element for
• @return mixed Value associated to the given key

Examples:

$map = Map::from( ['a' => 1, 'b' => 3] );

$map['b'];
// 3

offsetSet()

Sets the element at a given offset.

public function offsetSet( $key, $value )

• @param mixed $key Key to set the element for
• @param mixed $value New value set for the key

Examples:

$map = Map::from( ['a' => 1] );

$map['b'] = 2;
// ['a' => 1, 'b' => 2]

$map[0] = 4;
// ['a' => 1, 'b' => 2, 0 => 4]

offsetUnset()

Unsets the element at a given offset.

public function offsetUnset( $key )

• @param string $key Key for unsetting the item

Examples:

$map = Map::from( ['a' => 1] );

unset( $map['a'] );
// []

only()

Returns a new map with only those elements specified by the given keys.

public function only( $keys ) : self

• @param iterable|array|string|int $keys Keys of the elements that should be returned
• @return self New map with only the elements specified by the keys

Examples:

Map::from( ['a' => 1, 0 => 'b'] )->only( 'a' );
// ['a' => 1]

Map::from( ['a' => 1, 0 => 'b', 1 => 'c'] )->only( [0, 1] );
// [0 => 'b', 1 => 'c']

pad()

Fill up to the specified length with the given value

public function pad( int $size, $value = null ) : self

• @param int $size Total number of elements that should be in the list
• @return self Updated map for fluid interface

In case the given number is smaller than the number of element that are already in the list, the map is unchanged. If the size is positive, the new elements are padded on the right, if it's negative then the elements are padded on the left.

Examples:

Map::from( [1, 2, 3] )->pad( 5 );
// [1, 2, 3, null, null]

Map::from( [1, 2, 3] )->pad( -5 );
// [null, null, 1, 2, 3]

Map::from( [1, 2, 3] )->pad( 5, '0' );
// [1, 2, 3, '0', '0']

Map::from( [1, 2, 3] )->pad( 2 );
// [1, 2, 3]

partition()

Breaks the list of elements into the given number of groups.

public function partition( $num ) : self

• @param \Closure|int $number Function with (value, index) as arguments returning the bucket key or number of groups
• @return self New map

The keys of the original map are preserved in the returned map.

Examples:

Map::from( [1, 2, 3, 4, 5] )->partition( 3 );
// [[0 => 1, 1 => 2], [2 => 3, 3 => 4], [4 => 5]]

Map::from( [1, 2, 3, 4, 5] )->partition( function( $val, $idx ) {
	return $idx % 3;
} );
// [0 => [0 => 1, 3 => 4], 1 => [1 => 2, 4 => 5], 2 => [2 => 3]]

pipe()

Passes the map to the given callback and return the result.

public function pipe( \Closure $callback )

• @param \Closure $callback Function with map as parameter which returns arbitrary result
• @return mixed Result returned by the callback

Examples:

Map::from( ['a', 'b'] )->pipe( function( $map ) {
    return strrev( $map->join( '-' ) );
} );
// 'b-a'

pop()

Returns and removes the last element from the map.

public function pop()

• @return mixed Last element of the map or null if empty

Examples:

Map::from( ['a', 'b'] )->pop();
// 'b', map contains ['a']

pos

Returns the numerical index of the value.

public function pos( $value ) : int

• @param \Closure|mixed $value Value to search for or function with (item, key) parameters return TRUE if value is found
• @return int Position of the found value (zero based)

Examples:

Map::from( [4 => 'a', 8 => 'b'] )->pos( 'b' );
// 1

Map::from( [4 => 'a', 8 => 'b'] )->pos( function( $item, $key ) {
    return $item === 'b';
} );
// 1

Both examples will return "1" because the value "b" is at the second position and the returned index is zero based so the first item has the index "0".

prefix

Adds a prefix in front of each map entry.

public function prefix( $prefix )

• @param \Closure|string $prefix Function with map as parameter which returns arbitrary result
• @return self Updated map for fluid interface

Nested arrays are walked recusively so all entries at all levels are prefixed.

Examples:

Map::from( ['a', 'b'] )->prefix( '1-' );
// ['1-a', '1-b']

Map::from( ['a', ['b']] )->prefix( '1-' );
// ['1-a', ['1-b']]

Map::from( ['a', 'b'] )->prefix( function( $item, $key ) {
    return ( ord( $item ) + ord( $key ) ) . '-';
} );
// ['145-a', '147-b']

pull()

Returns and removes an element from the map by its key.

public function pull( $key, $default = null )

• @param mixed $key Key to retrieve the value for
• @param mixed $default Default value if key isn't available
• @return mixed Value from map or default value

Examples:

Map::from( ['a', 'b', 'c'] )->pull( 1 );
// 'b', map contains ['a', 'c']

Map::from( ['a', 'b', 'c'] )->pull( 'x', 'none' );
// 'none', map contains ['a', 'b', 'c']

push()

Adds an element onto the end of the map without returning a new map.

public function push( $value ) : self

• @param mixed $value Value to add to the end
• @return self Same map for fluid interface

Examples:

Map::from( ['a', 'b'] )->push( 'aa' );
// ['a', 'b', 'aa']

random()

Returns one or more random element from the map.

public function random( int $max = 1 ) : self

• @param int $max Maximum number of elements that should be returned
• @return self New map with key/element pairs from original map in random order
• @throws \InvalidArgumentException If requested number of elements is less than 1

The less elements are in the map, the less random the order will be, especially if the maximum number of values is high or close to the number of elements.

The keys of the original map are preserved in the returned map.

Examples:

Map::from( [2, 4, 8, 16] )->random();
// [2 => 8] or any other key/value pair

Map::from( [2, 4, 8, 16] )->random( 2 );
// [3 => 16, 0 => 2] or any other key/value pair

Map::from( [2, 4, 8, 16] )->random( 5 );
// [0 => 2,  1 => 4, 2 => 8, 3 => 16] in random order

reduce()

Iteratively reduces the array to a single value using a callback function.

public function reduce( callable $callback, $initial = null )

• @param callable $callback Function with (result, value) parameters and returns result
• @param mixed $initial Initial value when computing the result
• @return mixed Value computed by the callback function

Afterwards, the map will be empty.

Examples:

Map::from( [2, 8] )->reduce( function( $result, $value ) {
    return $result += $value;
}, 10 );
// 20 because 10 + 2 + 8 and map equals []

remove()

Removes one or more elements from the map by its keys without returning a new map.

public function remove( $keys ) : self

• @param iterable|array|string|int $keys List of keys
• @return self Same map for fluid interface

Examples:

Map::from( ['a' => 1, 2 => 'b'] )->remove( 'a' );
// [2 => 'b']

Map::from( ['a' => 1, 2 => 'b'] )->remove( [2, 'a'] );
// []

replace()

Replaces elements in the map with the given elements without returning a new map.

public function replace( iterable $elements, bool $recursive = true ) : self

• @param iterable $elements List of elements
• @param bool $recursive TRUE to replace recursively (default), FALSE to replace elements only
• @return self Updated map for fluid interface

The method is similar to merge() but also replaces elements with numeric keys. These would be added by merge() with a new numeric key.

Examples:

Map::from( ['a' => 1, 2 => 'b'] )->replace( ['a' => 2] );
// ['a' => 2, 2 => 'b']

Map::from( ['a' => 1, 'b' => ['c' => 3, 'd' => 4]] )->replace( ['b' => ['c' => 9]] );
// ['a' => 1, 'b' => ['c' => 9, 'd' => 4]]

reverse()

Reverses the element order without returning a new map.

public function reverse() : self

• @return self Updated map for fluid interface

Examples:

Map::from( ['a', 'b'] )->reverse();
// ['b', 'a']

rsort()

Sorts all elements in reverse order without maintaining the key association.

public function rsort( int $options = SORT_REGULAR ) : self

• @param int $options Sort options for rsort()
• @return self Updated map for fluid interface

The parameter modifies how the values are compared. Possible parameter values are:

• SORT_REGULAR : compare elements normally (don't change types)
• SORT_NUMERIC : compare elements numerically
• SORT_STRING : compare elements as strings
• SORT_LOCALE_STRING : compare elements as strings, based on the current locale or changed by setlocale()
• SORT_NATURAL : compare elements as strings using "natural ordering" like natsort()
• SORT_FLAG_CASE : use SORT_STRING|SORT_FLAG_CASE and SORT_NATURAL|SORT_FLAG_CASE to sort strings case-insensitively

The keys are NOT preserved and elements get a new index. No new map is created.

Examples:

Map::from( ['a' => 1, 'b' => 0] )->rsort();
// [0 => 1, 1 => 0]

Map::from( [0 => 'b', 1 => 'a'] )->rsort();
// [0 => 'b', 1 => 'a']

Map::from( [0 => 'C', 1 => 'b'] )->rsort();
// [0 => 'b', 1 => 'C']

Map::from( [0 => 'C', 1 => 'b'] )->rsort( SORT_STRING|SORT_FLAG_CASE );
// [0 => 'C', 1 => 'b'] because 'C' -> 'c' and 'c' > 'b'

search()

Searches the map for a given value and return the corresponding key if successful.

public function search( $value, $strict = true )

• @param mixed $value Item to search for
• @param bool $strict TRUE if type of the element should be checked too
• @return mixed|null Value from map or null if not found

Examples:

Map::from( ['a', 'b', 'c'] )->search( 'b' );
// 1

Map::from( [1, 2, 3] )->search( '2', true );
// null because the types doesn't match (int vs. string)

sep()

Sets the seperator for paths to values in multi-dimensional arrays or objects.

public static function sep( string $char ) : self

• @param string $char Separator character, e.g. "." for "key.to.value" instead of "key/to/value"
• @return self Same map for fluid interface

This method only changes the separator for the current map instance. To change the separator for all maps created afterwards, use the static Map::delimiter() method instead.

Examples:

Map::from( ['foo' => ['bar' => 'baz']] )->sep( '.' )->get( 'foo.bar' );
// 'baz'

set()

Sets an element in the map by key without returning a new map.

public function set( $key, $value ) : self

• @param mixed $key Key to set the new value for
• @param mixed $value New element that should be set
• @return self Same map for fluid interface

Examples:

Map::from( ['a'] )->set( 1, 'b' );
// [0 => 'a', 1 => 'b']

Map::from( ['a'] )->set( 0, 'b' );
// [0 => 'b']

shift()

Returns and removes the first element from the map.

public function shift()

• @return mixed|null Value from map or null if not found

Examples:

Map::from( ['a', 'b'] )->shift();
// 'a'

Map::from( [] )->shift();
// null

Performance note:

The bigger the list, the higher the performance impact because shift() reindexes all existing elements. Usually, it's better to reverse() the list and pop() entries from the list afterwards if a significant number of elements should be removed from the list:

$map->reverse()->pop();

instead of

$map->shift();

shuffle()

Shuffles the elements in the map without returning a new map.

public function shuffle( bool $assoc = false ) : self

• @param bool $assoc True to preserve keys, false to assign new keys
• @return self Updated map for fluid interface

Examples:

Map::from( [2 => 'a', 4 => 'b'] )->shuffle();
// ['a', 'b'] in random order with new keys

Map::from( [2 => 'a', 4 => 'b'] )->shuffle( true );
// [2 => 'a', 4 => 'b'] in random order with keys preserved

skip()

Returns a new map with the given number of items skipped.

public function skip( $offset ) : self

• @param \Closure|int $offset Number of items to skip or function($item, $key) returning true for skipped items
• @return self New map

The keys of the items returned in the new map are the same as in the original one.

Examples:

Map::from( [1, 2, 3, 4] )->skip( 2 );
// [2 => 3, 3 => 4]

Map::from( [1, 2, 3, 4] )->skip( function( $item, $key ) {
    return $item < 4;
} );
// [3 => 4]

slice()

Returns a map with the slice from the original map.

public function slice( int $offset, int $length = null ) : self

• @param int $offset Number of elements to start from
• @param int|null $length Number of elements to return or NULL for no limit
• @return self New map

The rules for offsets are:

• If offset is non-negative, the sequence will start at that offset
• If offset is negative, the sequence will start that far from the end

Similar for the length:

• If length is given and is positive, then the sequence will have up to that many elements in it
• If the array is shorter than the length, then only the available array elements will be present
• If length is given and is negative then the sequence will stop that many elements from the end
• If it is omitted, then the sequence will have everything from offset up until the end

Examples:

Map::from( ['a', 'b', 'c'] )->slice( 1 );
// ['b', 'c']

Map::from( ['a', 'b', 'c'] )->slice( 1, 1 );
// ['b']

Map::from( ['a', 'b', 'c', 'd'] )->slice( -2, -1 );
// ['c']

some()

Tests if at least one element passes the test or is part of the map.

public function some( $values, bool $strict = false ) : bool

• @param \Closure|iterable|mixed $values Anonymous function with (item, key) parameter, element or list of elements to test against
• @param bool $strict TRUE to check the type too, using FALSE '1' and 1 will be the same
• @return bool TRUE if at least one element is available in map, FALSE if the map contains none of them

Examples:

Map::from( ['a', 'b'] )->some( 'a' );
// true

Map::from( ['a', 'b'] )->some( ['a', 'c'] );
// true

Map::from( ['a', 'b'] )->some( function( $item, $key ) {
    return $item === 'a'
} );
// true

Map::from( ['a', 'b'] )->some( ['c', 'd'] );
// false

Map::from( ['1', '2'] )->some( [2], true );
// false

sort()

Sorts all elements without maintaining the key association.

public function sort( int $options = SORT_REGULAR ) : self

• @param int $options Sort options for sort()
• @return self Updated map for fluid interface

The parameter modifies how the values are compared. Possible parameter values are:

• SORT_REGULAR : compare elements normally (don't change types)
• SORT_NUMERIC : compare elements numerically
• SORT_STRING : compare elements as strings
• SORT_LOCALE_STRING : compare elements as strings, based on the current locale or changed by setlocale()
• SORT_NATURAL : compare elements as strings using "natural ordering" like natsort()
• SORT_FLAG_CASE : use SORT_STRING|SORT_FLAG_CASE and SORT_NATURAL|SORT_FLAG_CASE to sort strings case-insensitively

The keys are NOT preserved and elements get a new index. No new map is created.

Examples:

Map::from( ['a' => 1, 'b' => 0] )->sort();
// [0 => 0, 1 => 1]

Map::from( [0 => 'b', 1 => 'a'] )->sort();
// [0 => 'a', 1 => 'b']

splice()

Removes a portion of the map and replace it with the given replacement, then return the updated map.

public function splice( int $offset, int $length = null, $replacement = [] ) : self

• @param int $offset Number of elements to start from
• @param int|null $length Number of elements to remove, NULL for all
• @param mixed $replacement List of elements to insert
• @return self New map

The rules for offsets are:

• If offset is non-negative, the sequence will start at that offset
• If offset is negative, the sequence will start that far from the end

Similar for the length:

• If length is given and is positive, then the sequence will have up to that many elements in it
• If the array is shorter than the length, then only the available array elements will be present
• If length is given and is negative then the sequence will stop that many elements from the end
• If it is omitted, then the sequence will have everything from offset up until the end

Examples:

Map::from( ['a', 'b', 'c'] )->splice( 1 );
// ['b', 'c'] and map contains ['a']

Map::from( ['a', 'b', 'c'] )->splice( 1, 1, ['x', 'y'] );
// ['b'] and map contains ['a', 'x', 'y', 'c']

suffix

Adds a suffix at the end of each map entry.

public function suffix( $suffix )

• @param \Closure|string $suffix Function with map as parameter which returns arbitrary result
• @return self Updated map for fluid interface

Nested arrays are walked recusively so all entries at all levels are suffixed.

Examples:

Map::from( ['a', 'b'] )->suffix( '-1' );
// ['a-1', 'b-1']

Map::from( ['a', ['b']] )->suffix( '-1' );
// ['a-1', ['b-1']]

Map::from( ['a', 'b'] )->suffix( function( $item, $key ) {
    return '-' . ( ord( $item ) + ord( $key ) );
} );
// ['a-145', 'b-147']

sum()

Returns the sum of all integer and float values in the map.

public function sum( string $col = null ) : int

• @param string|null $col Key in the nested array or object to sum up
• @return mixed Sum of all elements or 0 if there are no elements in the map

This does also work to map values from multi-dimensional arrays by passing the keys of the arrays separated by the delimiter ("/" by default), e.g. key1/key2/key3 to get val from ['key1' => ['key2' => ['key3' => 'val']]]. The same applies to public properties of objects or objects implementing __isset() and __get() methods.

Examples:

Map::from( [1, 3, 5] )->sum();
// 9

Map::from( [1, 'sum', 5] )->sum();
// 6

Map::from( [['p' => 30], ['p' => 50], ['p' => 10]] )->sum( 'p' );
// 90

Map::from( [['i' => ['p' => 30]], ['i' => ['p' => 50]]] )->sum( 'i/p' );
// 80

take()

Returns a new map with the given number of items.

public function take( int $size, $offset = 0 ) : self

• @param int $size Number of items to return
• @param \Closure|int $offset Number of items to skip or function($item, $key) returning true for skipped items
• @return self New map

The keys of the items returned in the new map are the same as in the original one.

Examples:

Map::from( [1, 2, 3, 4] )->take( 2 );
// [0 => 1, 1 => 2]

Map::from( [1, 2, 3, 4] )->take( 2, 1 );
// [1 => 2, 2 => 3]

Map::from( [1, 2, 3, 4] )->take( 2, -2 );
// [2 => 3, 3 => 4]

Map::from( [1, 2, 3, 4] )->take( 2, function( $item, $key ) {
    return $item < 2;
} );
// [1 => 2, 2 => 3]

tap()

Passes a clone of the map to the given callback.

public function tap( callable $callback ) : self

• @param callable $callback Function receiving ($map) parameter
• @return self Same map for fluid interface

Use it to "tap" into a chain of methods to check the state between two method calls. The original map is not altered by anything done in the callback.

Examples:

Map::from( [3, 2, 1] )->rsort()->tap( function( $map ) {
    print_r( $map->remove( 0 )->toArray() );
} )->first();
// 1

It will sort the list in reverse order([1, 2, 3]), then prints the items ([2, 3]) without the first one in the function passed to tap() and returns the first item ("1") at the end.

times()

Creates a new map by invoking the closure the given number of times.

public static function times( int $num, \Closure $callback )

• @param int $num Number of times the function is called
• @param \Closure $callback Function with (value, key) parameters and returns new value

Examples:

Map::times( 3, function( $num ) {
    return $num * 10;
} );
// [0 => 0, 1 => 10, 2 => 20]

Map::times( 3, function( $num, &$key ) {
    $key = $num * 2;
    return $num * 5;
} );
// [0 => 0, 2 => 5, 4 => 10]

Map::times( 2, function( $num ) {
    return new \stdClass();
} );
// [0 => new \stdClass(), 1 => new \stdClass()]

toArray()

Returns the elements as a plain array.

public function toArray() : array

• @return array Plain array

Examples:

Map::from( ['a'] )->toArray();
// ['a']

toJson()

Returns the elements encoded as JSON string.

public function toJson( int $options = 0 ) : string

• @param int $options Combination of JSON_* constants
• @return string Array encoded as JSON string

There are several options available to modify the JSON string which are described in the PHP json_encode() manual. The parameter can be a single JSON_* constant or a bitmask of several constants combine by bitwise OR (|), e.g.:

JSON_FORCE_OBJECT|JSON_HEX_QUOT

Examples:

Map::from( ['a', 'b'] )->toJson();
// '["a","b"]'

Map::from( ['a' => 'b'] )->toJson();
// '{"a":"b"}'

Map::from( ['a', 'b'] )->toJson( JSON_FORCE_OBJECT );
// '{"0":"a", "1":"b"}'

toUrl()

Creates a HTTP query string from the map elements.

public function toUrl() : string

• @return string Parameter string for GET requests

Examples:

Map::from( ['a' => 1, 'b' => 2] )->toUrl();
// a=1&b=2

Map::from( ['a' => ['b' => 'abc', 'c' => 'def'], 'd' => 123] )->toUrl();
// a%5Bb%5D=abc&a%5Bc%5D=def&d=123

transpose()

Exchanges rows and columns for a two dimensional map.

public function transpose() : self

• @return self New map

Examples:

Map::from( [
  ['name' => 'A', 2020 => 200, 2021 => 100, 2022 => 50],
  ['name' => 'B', 2020 => 300, 2021 => 200, 2022 => 100],
  ['name' => 'C', 2020 => 400, 2021 => 300, 2022 => 200],
] )->transpose();
/*
[
  'name' => ['A', 'B', 'C'],
  2020 => [200, 300, 400],
  2021 => [100, 200, 300],
  2022 => [50, 100, 200]
]
*/

Map::from( [
  ['name' => 'A', 2020 => 200, 2021 => 100, 2022 => 50],
  ['name' => 'B', 2020 => 300, 2021 => 200],
  ['name' => 'C', 2020 => 400]
] );
/*
[
  'name' => ['A', 'B', 'C'],
  2020 => [200, 300, 400],
  2021 => [100, 200],
  2022 => [50]
]
*/

traverse()

Traverses trees of nested items passing each item to the callback.

public function traverse( \Closure $callback = null, string $nestKey = 'children' ) : self

• @param \Closure|null $callback Callback with (entry, key, level) arguments, returns the entry added to result
• @param string $nestKey Key to the children of each item
• @return self New map with all items as flat list

This does work for nested arrays and objects with public properties or objects implementing __isset() and __get() methods. To build trees of nested items, use the tree() method.

Examples:

Map::from( [[
  'id' => 1, 'pid' => null, 'name' => 'n1', 'children' => [
    ['id' => 2, 'pid' => 1, 'name' => 'n2', 'children' => []],
    ['id' => 3, 'pid' => 1, 'name' => 'n3', 'children' => []]
  ]
]] )->traverse();
/*
[
  ['id' => 1, 'pid' => null, 'name' => 'n1', 'children' => [...]],
  ['id' => 2, 'pid' => 1, 'name' => 'n2', 'children' => []],
  ['id' => 3, 'pid' => 1, 'name' => 'n3', 'children' => []],
]
*/

Map::from( [[
  'id' => 1, 'pid' => null, 'name' => 'n1', 'children' => [
    ['id' => 2, 'pid' => 1, 'name' => 'n2', 'children' => []],
    ['id' => 3, 'pid' => 1, 'name' => 'n3', 'children' => []]
  ]
]] )->traverse( function( $entry, $key, $level ) {
  return str_repeat( '-', $level ) . '- ' . $entry['name'];
} );
// ['- n1', '-- n2', '-- n3']

Map::from( [[
  'id' => 1, 'pid' => null, 'name' => 'n1', 'nodes' => [
    ['id' => 2, 'pid' => 1, 'name' => 'n2', 'nodes' => []]
  ]
]] )->traverse( null, 'nodes' );
/*
[
  ['id' => 1, 'pid' => null, 'name' => 'n1', 'nodes' => [...]],
  ['id' => 2, 'pid' => 1, 'name' => 'n2', 'nodes' => []],
]
*/

tree()

Creates a tree structure from the list items.

public function tree( string $idKey, string $parentKey, string $nestKey = 'children' ) : self

• @param string $idKey Name of the key with the unique ID of the node
• @param string $parentKey Name of the key with the ID of the parent node
• @param string $nestKey Name of the key with will contain the children of the node
• @return self New map with one or more root tree nodes

Use this method to rebuild trees e.g. from database records. To traverse trees, use the traverse() method.

Examples:

Map::from( [
  ['id' => 1, 'pid' => null, 'lvl' => 0, 'name' => 'n1'],
  ['id' => 2, 'pid' => 1, 'lvl' => 1, 'name' => 'n2'],
  ['id' => 3, 'pid' => 2, 'lvl' => 2, 'name' => 'n3'],
  ['id' => 4, 'pid' => 1, 'lvl' => 1, 'name' => 'n4'],
  ['id' => 5, 'pid' => 3, 'lvl' => 2, 'name' => 'n5'],
  ['id' => 6, 'pid' => 1, 'lvl' => 1, 'name' => 'n6'],
] )->tree( 'id', 'pid' );
/*
[1 => [
  'id' => 1, 'pid' => null, 'lvl' => 0, 'name' => 'n1', 'children' => [
    2 => ['id' => 2, 'pid' => 1, 'lvl' => 1, 'name' => 'n2', 'children' => [
      3 => ['id' => 3, 'pid' => 2, 'lvl' => 2, 'name' => 'n3', 'children' => []]
    ]],
    4 => ['id' => 4, 'pid' => 1, 'lvl' => 1, 'name' => 'n4', 'children' => [
      5 => ['id' => 5, 'pid' => 3, 'lvl' => 2, 'name' => 'n5', 'children' => []]
    ]],
    6 => ['id' => 6, 'pid' => 1, 'lvl' => 1, 'name' => 'n6', 'children' => []]
  ]
]]
*/

To build the tree correctly, the items must be in order or at least the nodes of the lower levels must come first. For a tree like this:

n1
|- n2
|  |- n3
|- n4
|  |- n5
|- n6

Accepted item order:

• in order: n1, n2, n3, n4, n5, n6
• lower levels first: n1, n2, n4, n6, n3, n5

If your items are unordered, apply usort() first to the map entries, e.g.

Map::from( [['id' => 3, 'lvl' => 2], ...] )->usort( function( $item1, $item2 ) {
  return $item1['lvl'] <=> $item2['lvl'];
} );

uasort()

Sorts all elements using a callback and maintains the key association.

public function uasort( callable $callback ) : self

• @param callable $callback Function with (itemA, itemB) parameters and returns -1 (<), 0 (=) and 1 (>)
• @return self Updated map for fluid interface

The given callback will be used to compare the values. The callback must accept two parameters (item A and B) and must return -1 if item A is smaller than item B, 0 if both are equal and 1 if item A is greater than item B. Both, a method name and an anonymous function can be passed.

The keys are preserved using this method and no new map is created.

Examples:

Map::from( ['a' => 'B', 'b' => 'a'] )->uasort( 'strcasecmp' );
// ['b' => 'a', 'a' => 'B']

Map::from( ['a' => 'B', 'b' => 'a'] )->uasort( function( $itemA, $itemB ) {
    return strtolower( $itemA ) <=> strtolower( $itemB );
} );
// ['b' => 'a', 'a' => 'B']

uksort()

Sorts the map elements by their keys using a callback.

public function uksort( callable $callback ) : self

• @param callable $callback Function with (keyA, keyB) parameters and returns -1 (<), 0 (=) and 1 (>)
• @return self Updated map for fluid interface

The given callback will be used to compare the keys. The callback must accept two parameters (key A and B) and must return -1 if key A is smaller than key B, 0 if both are equal and 1 if key A is greater than key B. Both, a method name and an anonymous function can be passed.

The keys are preserved using this method and no new map is created.

Examples:

Map::from( ['B' => 'a', 'a' => 'b'] )->uksort( 'strcasecmp' );
// ['a' => 'b', 'B' => 'a']

Map::from( ['B' => 'a', 'a' => 'b'] )->uksort( function( $keyA, $keyB ) {
    return strtolower( $keyA ) <=> strtolower( $keyB );
} );
// ['a' => 'b', 'B' => 'a']

union()

Builds a union of the elements and the given elements without returning a new map. Existing keys in the map will not be overwritten

public function union( iterable $elements ) : self

• @param iterable $elements List of elements
• @return self Updated map for fluid interface

If list entries should be overwritten, use merge() instead.

Examples:

Map::from( [0 => 'a', 1 => 'b'] )->union( [0 => 'c'] );
// [0 => 'a', 1 => 'b'] because the key 0 isn't overwritten

Map::from( ['a' => 1, 'b' => 2] )->union( ['c' => 1] );
// ['a' => 1, 'b' => 2, 'c' => 1]

unique()

Returns only unique elements from the map in a new map

public function unique() : self

• @return self New map

Two elements are condidered equal if comparing their string representions returns TRUE:

(string) $elem1 === (string) $elem2

The keys of the elements are preserved in the new map.

Examples:

Map::from( [0 => 'a', 1 => 'b', 2 => 'b', 3 => 'c'] )->unique();
// [0 => 'a', 1 => 'b', 3 => 'c']

unshift()

Pushes an element onto the beginning of the map without returning a new map.

public function unshift( $value, $key = null ) : self

• @param mixed $value Item to add at the beginning
• @param mixed $key Key for the item
• @return self Same map for fluid interface

Examples:

Map::from( ['a', 'b'] )->unshift( 'd' );
// ['d', 'a', 'b']

Map::from( ['a', 'b'] )->unshift( 'd', 'first' );
// ['first' => 'd', 0 => 'a', 1 => 'b']

usort()

Sorts all elements using a callback without maintaining the key association.

public function usort( callable $callback ) : self

• @param callable $callback Function with (itemA, itemB) parameters and returns -1 (<), 0 (=) and 1 (>)
• @return self Updated map for fluid interface

The given callback will be used to compare the values. The callback must accept two parameters (item A and B) and must return -1 if item A is smaller than item B, 0 if both are equal and 1 if item A is greater than item B. Both, a method name and an anonymous function can be passed.

The keys are NOT preserved and elements get a new index. No new map is created.

Examples:

Map::from( ['a' => 'B', 'b' => 'a'] )->usort( 'strcasecmp' );
// [0 => 'a', 1 => 'B']

Map::from( ['a' => 'B', 'b' => 'a'] )->usort( function( $itemA, $itemB ) {
    return strtolower( $itemA ) <=> strtolower( $itemB );
} );
// [0 => 'a', 1 => 'B']

Performance note:

The bigger the list, the higher the performance impact because unshift() needs to create a new list and copies all existing elements to the new array. Usually, it's better to push() new entries at the end and reverse() the list afterwards:

$map->push( 'a' )->push( 'b' )->reverse();

instead of

$map->unshift( 'a' )->unshift( 'b' );

values()

Resets the keys and return the values in a new map.

public function values() : self

• @return self New map of the values

Examples:

Map::from( ['x' => 'b', 2 => 'a', 'c'] )->values();
// [0 => 'b', 1 => 'a', 2 => 'c']

walk()

Applies the given callback to all elements.

public function walk( callable $callback, $data = null, bool $recursive = true ) : self

• @param callable $callback Function with (item, key, data) parameters
• @param mixed $data Arbitrary data that will be passed to the callback as third parameter
• @param bool $recursive TRUE to traverse sub-arrays recursively (default), FALSE to iterate Map elements only
• @return self Map for fluid interface

To change the values of the Map, specify the value parameter as reference (&$value). You can only change the values but not the keys nor the array structure.

By default, Map elements which are arrays will be traversed recursively. To iterate over the Map elements only, pass FALSE as third parameter.

Examples:

Map::from( ['a', 'B', ['c', 'd'], 'e'] )->walk( function( &$value ) {
    $value = strtoupper( $value );
} );
// ['A', 'B', ['C', 'D'], 'E']

Map::from( [66 => 'B', 97 => 'a'] )->walk( function( $value, $key ) {
    echo 'ASCII ' . $key . ' is ' . $value . "\n";
} );
/*
ASCII 66 is B
ASCII 97 is a
*/

Map::from( [1, 2, 3] )->walk( function( &$value, $key, $data ) {
    $value = $data[$value] ?? $value;
}, [1 => 'one', 2 => 'two'] );
// ['one', 'two', 3]

where()

Filters the list of elements by a given condition.

public function where( string $key, string $op, $value ) : self

• @param string $key Key or path of the value of the array or object used for comparison
• @param string $op Operator used for comparison
• @param mixed $value Value used for comparison

Available operators are:

• '==' : Equal
• '===' : Equal and same type
• '!=' : Not equal
• '!==' : Not equal and same type
• '<=' : Smaller than an equal
• '>=' : Greater than an equal
• '<' : Smaller
• '>' : Greater
• 'in' : Array of value which are in the list of values
• '-' : Values between array of start and end value, e.g. [10, 100] (inclusive)

Examples:

Map::from( [
  ['id' => 1, 'type' => 'name'],
  ['id' => 2, 'type' => 'short'],
] )->where( 'type', '==', 'name' );
/*
[
    ['id' => 1, 'type' => 'name']
]
*/

Map::from( [
  ['id' => 3, 'price' => 10],
  ['id' => 4, 'price' => 50],
] )->where( 'price', '>', 20 );
/*
[
    ['id' => 4, 'price' => 50]
]
*/

Map::from( [
  ['id' => 3, 'price' => 10],
  ['id' => 4, 'price' => 50],
] )->where( 'price', 'in', [10, 25] );
/*
[
    ['id' => 3, 'price' => 10]
]
*/

Map::from( [
  ['id' => 3, 'price' => 10],
  ['id' => 4, 'price' => 50],
] )->where( 'price', '-', [10, 100] );
/*
[
    ['id' => 3, 'price' => 10],
    ['id' => 4, 'price' => 50]
]
*/

Map::from( [
  ['item' => ['id' => 3, 'price' => 10]],
  ['item' => ['id' => 4, 'price' => 50]],
] )->where( 'item/price', '>', 30 );
/*
[
    ['id' => 4, 'price' => 50]
]
*/

zip()

Merges the values of all arrays at the corresponding index.

public function zip( $array1, ... ) : self

• @param array|\Traversable|\Iterator $array1 List of arrays to merge with at the same position
• @return self New map of arrays

Examples:

Map::from( [1, 2, 3] )->zip( ['one', 'two', 'three'], ['uno', 'dos', 'tres'] );
/*
[
    [1, 'one', 'uno'],
    [2, 'two', 'dos'],
    [3, 'three', 'tres'],
]
*/

Custom methods

Most of the time, it's enough to pass an anonymous function to the pipe() method to implement custom functionality in map objects:

Map::from( ['a', 'b'] )->pipe( function( $map ) {
    return strrev( $map->join( '-' ) );
} );

If you need some functionality more often and at different places in your source code, than it's better to register a custom method once and only call it everywhere:

Map::method( 'strrev', function( $sep ) {
    return strrev( join( '-', $this->list ) );
} );
Map::from( ['a', 'b'] )->strrev( '-' );

Make sure, you register the method before using it. You can pass arbitrary parameters to your function and it has access to the internas of the map. Thus, your function can use $this to call all available methods:

Map::method( 'notInBoth', function( iterable $elements ) {
    return new self( $this->diff( $elements ) + Map::from( $elements )->diff( $this->items ) );
} );

Your custom method has access to $this->items array which contains the map elements and can also use the internal $this->getArray( iterable $list ) method to convert iterable parameters (arrays, generators and objects implementing \Traversable) to plain arrays:

Map::method( 'combine', function( iterable $keys ) {
    return new self( array_combine( $this->getArray( $keys ), $this-items ) );
} );

Performance

The performance most methods only depends on the array_* function that are used internally by the Map class. If the methods of the Map class contains additional code, it's optimized to be as fast as possible.

Creating Map vs. array

Creating an map object with an array instead of creating a plain array only is significantly slower (ca. 10x) but in absolute values we are talking about nano seconds. It will only get notable if you create 10,000 map objects instead of 10,000 arrays. Then, creating maps will last ca. 10ms longer.

Usually, this isn't much of a problem because applications create arrays with lots of elements instead of 10,000+ arrays. Nevertheless, if your application creates a very large number of arrays within one area, you should think about avoiding map objects in that area.

If you use the map() function or Map::from() to create map objects, then be aware that this adds another function call. Using these methods for creating the map object lasts around 1.1x resp. 1.3x compared to the time for new Map(). Conclusion: Using new Map() is fastest and map() is faster than Map::from().

Populating Map vs. array

Adding an element to a Map object using $map[] = 'a' is ca. 5x slower than doing the same on a plain array. This is because the method offsetSet() will be called instead of adding the new element to the array directly. This applies to the $map->push( 'a' ) method too.

When creating arrays in loops, you should populate the array first and then create a Map object from the the array:

$list = [];
for( $i = 0; $i < 1000; $i++ ) {
	$list[] = $i;
}
$map = map( $list );

The array is NOT copied when creating the Map object so there's virtually no performance loss using the Map afterwards.

Using Map methods vs. language constructs

Language constructs such as empty(), count() or isset() are faster than calling a method and using $map->isEmpty() or $map->count() is ca. 4x slower.

Again, we are talking about nano seconds. For 10,000 calls to empty( $array ) compared to $map->isEmpty(), the costs are around 4ms in total.

Using Map methods vs. array_* functions

Using the Map methods instead of the array_* functions adds an additional method call. Internally, the Map objects uses the same array_* functions but offers a much more usable interface.

The time for the additional method call is almost neglectable because the array_* methods needs much longer to perform the operation on the array elements depending on the size of the array.

Using anonymous functions

Several Map methods support passing an anonymous function that is applied to every element of the map. PHP needs some time to call the passed function and to execute its code. Depending on the number of elements, this may have a significant impact on performance!

The pipe() method of the Map object is an exception because it receives the whole map object instead of each element separately. Its performance mainly depends on the implemented code:

$map->pipe( function( Map $map ) {
	// perform operations on the map
} );

Using shift() and unshift()

Both methods are costly, especially on large arrays. The used array_shift() and array_unshift() functions will reindex all numerical keys of the array.

If you want to reduce or create a large list of elements from the beginning in an iterative way, you should use reverse() and pop()/push() instead of shift() and unshift():

$map->reverse()->pop(); // use pop() until it returns NULL
$map->push( 'z' )->push( 'y' )->push( 'x' )->reverse(); // use push() for adding

Upgrade guide

1.x -> 2.x

jQuery style method calls

You can call methods of objects in a map like this:

// MyClass implements setStatus() (returning $this) and getCode() (initialized by constructor)

$map = Map::from( ['a' => new MyClass( 'x' ), 'b' => new MyClass( 'y' )] );
$map->setStatus( 1 )->getCode()->toArray();

Before, it was checked if the objects really implement setStatus() and getCode().

This isn't the case any more to avoid returning an empty map if the method name is wrong or the called method is implemented using the __call() magic method. Now, PHP generates a fatal error if the method isn't implemented by all objects.

Second equals() parameter

The second parameter of the equals() method ($assoc) to compare keys too has been removed. Use the is() method instead:

// 1.x
map( ['one' => 1] )->equals( ['one' => 1], true );

// 2.x
map( ['one' => 1] )->is( ['one' => 1] );

New find() argument

A default value or exception object can be passed to the find() method now as second argument. The $reverse argument has been moved to the third position.

// 1.x
Map::from( ['a', 'c', 'e'] )->find( function( $value, $key ) {
    return $value >= 'b';
}, true );

// 2.x
Map::from( ['a', 'c', 'e'] )->find( function( $value, $key ) {
    return $value >= 'b';
}, null, true );

groupBy() semantic change

If the key passed to groupBy() didn't exist, the items have been grouped using the given key. Now, an empty string is used as key to offer easier checking and sorting of the keys.

Map::from( [
    10 => ['aid' => 123, 'code' => 'x-abc'],
] )->groupBy( 'xid' );

// 1.x
[
    'xid' => [
        10 => ['aid' => 123, 'code' => 'x-abc']
    ]
]

// 2.x
[
    '' => [
        10 => ['aid' => 123, 'code' => 'x-abc']
    ]
]

offsetExists() semantic change

To be consistent with typical PHP behavior, the offsetExists() method use isset() instead of array_key_exists() now. This changes the behavior when dealing with NULL values.

$m = Map::from( ['foo' => null] );

// 1.x
isset( $m['foo'] ); // true

// 2.x
isset( $m['foo'] ); // false

Renamed split() method

The static Map::split() method has been renamed to Map::explode() and the argument order has changed. This avoids conflicts with the Laravel split() method and is in line with the PHP explode() method.

// 1.x
Map::split( 'a,b,c', ',' );

// 2.x
Map::explode( ',', 'a,b,c' );