LineReader
LineReader is a library to read large files line by line in a memory efficient (constant) way.
Install
Via Composer
$ composer require bcremer/line-readerUsage
Given we have a textfile (some/file.txt) with lines like:
Line 1
Line 2
Line 3
Line 4
Line 5
Line 6
Line 7
Line 8
Line 9
Line 10
Also let's assume the namespace is imported to keep the examples dense:
use Bcremer\LineReader\LineReader;
Read forwards
foreach (LineReader::readLines('some/file.txt') as $line) {
echo $line . "\n"
}The output will be:
Line 1
Line 2
Line 3
Line 4
Line 5
...
To set an offset or a limit use the \LimitIterator:
$lineGenerator = LineReader::readLines('some/file.txt');
$lineGenerator = new \LimitIterator($lineGenerator, 2, 5);
foreach ($lineGenerator as $line) {
echo $line . "\n"
}Will output line 3 to 7
Line 3
Line 4
Line 5
Line 6
Line 7
Read backwards
foreach (LineReader::readLinesBackwards('some/file.txt') as $line) {
echo $line;
}Line 10
Line 9
Line 8
Line 7
Line 6
...
Example: Read the last 5 lines in forward order:
$lineGenerator = LineReader::readLinesBackwards('some/file.txt');
$lineGenerator = new \LimitIterator($lineGenerator, 0, 5);
$lines = array_reverse(iterator_to_array($lineGenerator));
foreach ($line as $line) {
echo $line;
}Line 6
Line 7
Line 8
Line 9
Line 10
Testing
$ composer test$ TEST_MAX_LINES=200000 composer testLicense
The MIT License (MIT). Please see License File for more information.