Meituan-Dianping / Easysequence

EasySequence is a powerful fundamental library to process sequence type, such as array, set, dictionary. Each type of object which conforms to NSFastEnumeration protocol can be initialzed to an EZSequence instance, then you can operate with it. Finally, you can transfer it back to the original type.

Requirements

iOS 8.0 or later.

Installation

EasySequence is available through CocoaPods. To install it, simply add the following line to your Podfile:

pod 'EasySequence'

To run the example project, clone the repo, and run pod install from the Example directory first.

Features

Creating

• can be initialized from any object which conforms to NSFastEnumeration protocol.

Enumerating

• enumerate using forEach:
• enumerate using forEachWithIndex:
• enumerate using fast enumeration
• enumerate using NSEnumerator

Operations

• map
• flatten map
• filter
• select
• reject
• take
• skip
• any
• zip
• reduce
• group by
• first object
• first object where
• first index where

Transfer

• An object which conforms to EZSTransfer protocol can get an instance which transfer from EZSequence.

Thread-Safety Type

We provides thread-safety types as below:

• EZSArray
• EZSWeakArray
• EZSOrderedSet
• EZSWeakOrderedSet
• EZSQueue

Weak Container

EZSWeakArray and EZSWeakOrderedSet form weak reference to their's items.

Example

Create a sequence

A sequence, represented by the EZSequence type, is a particular order in which ralated objects, or objects follow each other. For example, a NSArray or a NSSet is sequence ather than EZSequence.

An EZSequence can be initialized from any object which conforms to NSFastEnumeration protocol.

NSArray *array = @[@1, @2, @3];
EZSequence *sequence = [[EZSequence alloc] initWithOriginSequence:array];

Enumerating

• Enumerate using fast enumeration

EZSequence *sequence = [[EZSequence alloc] initWithOriginSequence:@[@1, @2, @3]];
NSMutableArray *receive = [NSMutableArray array];
for (id item in sequence) {
    [receive addObject:item];
}

• Enumerate using NSEnumerator

EZSequence<NSNumber *> *sequence = [[EZSequence alloc] initWithOriginSequence:@[@1, @2, @3]];
NSMutableArray<NSNumber *> *receive = [NSMutableArray array];

NSEnumerator<NSNumber *> *enumerator = [sequence objectEnumerator];
for (id item in enumerator) {
    [receive addObject:item];
}

• Enumerate using block-based enumeration

EZSequence<NSNumber *> *sequence = [[EZSequence alloc] initWithOriginSequence:@[@1, @2, @3]];
NSMutableArray *receive = [NSMutableArray array];
[sequence forEach:^(NSNumber *item) {
    [receive addObject:item];
}];

[sequence forEachWithIndex:^(NSNumber * _Nonnull item, NSUInteger index) {
    [receive addObject:item];
}];

[sequence forEachWithIndexAndStop:^(NSNumber * _Nonnull item, NSUInteger index, BOOL * _Nonnull stop) {
    if (index == 2) {
        *stop = YES;
    }
    [receive addObject:item];
}];

Operations

• map

EZSequence<NSString *> *sequence = EZS_Sequence(@[@"111", @"222", @"333"]);
EZSequence<NSNumber *> *mappedSequence = [sequence map:^id _Nonnull(NSString * _Nonnull value) {
    return @(value.integerValue);
}];
// mappedSequence => @111, @222, @333

• select

EZSequence<NSNumber *> *sequence = [@[@1, @2, @3, @4, @5, @6] EZS_asSequence];
EZSequence<NSNumber *> *oddNumbers = [sequence select:^BOOL(NSNumber * _Nonnull value) {
    return value.integerValue % 2 == 1;
}];
// oddNumbers => @1, @3, @5

• filter

EZSequence *seq = EZS_Sequence(@[@"1", @"2", @"3", @"4", @"5"]);
EZSequence *filteredSeq = [seq filter:EZS_not(EZS_isEqual(@"4"))];
// filteredSeq = > @"1", @"2", @"3", @"5"

• zip

NSArray *a = @[@1, @2, @3];
NSArray *b = @[@"a", @"b"];
EZSequence<EZSequence *> *zippedSeq = [EZSequence zip:@[a, b]];
// zippedSeq => @[@1, @"a"], @[@2, @"b"]

For more examples and help, see also our unit test and API comments.

Transfer Protocol

An object which conforms to EZSTransfer protocol can get an instance which transfer from EZSequence.

EZSequence *sequence = [[EZSequence alloc] initWithOriginSequence:@[@1, @2, @3, @2]];

// transfer to a `NSArray`
NSArray *array = [sequence as:NSArray.class];
// array => @1, @2, @3, @2

// transfer to a `NSSet`
NSSet *set = [sequence as:NSSet.class];
// set => @1, @2, @3

// transfer to a `NSOrderedSet`
NSOrderedSet *orderedSet = [sequence as:NSOrderedSet.class];
// orderedSet => @1, @2, @3

Author

William Zang, [email protected]
姜沂, [email protected]
Qin Hong, [email protected]
SketchK, [email protected]

License

EasySequence is available under the MIT license. See the LICENSE file for more info.