Ds\Sequence::filter
(PECL ds >= 1.0.0)
Ds\Sequence::filter — Creates a new sequence using a callable to determine which values to include
Description
abstract public Ds\Sequence::filter(callable $callback = ?): Ds\Sequence
Creates a new sequence using a callable to determine which values to include.
Parameters
-
callback
-
callback(mixed $value): bool
Optional callable which returns
true
if the value should be included,false
otherwise.If a callback is not provided, only values which are
true
(see converting to boolean) will be included.
Return Values
A new sequence containing all the values for which either the callback
returned true
, or all values that convert to true
if a callback
was not provided.
Examples
Example #1 Ds\Sequence::filter() example using callback function
<?php $sequence = new \Ds\Vector([1, 2, 3, 4, 5]); var_dump($sequence->filter(function($value) { return $value % 2 == 0; })); ?>
The above example will output something similar to:
object(Ds\Vector)#3 (2) { [0]=> int(2) [1]=> int(4) }
Example #2 Ds\Sequence::filter() example without a callback function
<?php $sequence = new \Ds\Vector([0, 1, 'a', true, false]); var_dump($sequence->filter()); ?>
The above example will output something similar to:
object(Ds\Vector)#2 (3) { [0]=> int(1) [1]=> string(1) "a" [2]=> bool(true) }
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https://www.php.net/manual/en/ds-sequence.filter.php