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 Ds\Sequence::filter ([ callable $callback ] )

Creates a new sequence using a callable to determine which values to include.

Parameters

callback

bool callback ( mixed $value )

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([12345]);

var_dump($sequence->filter(function($value) {
    return 
$value == 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([01'a'truefalse]);

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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