(PECL ds >= 1.0.0)
Ds\Sequence::filter — Creates a new sequence using a callable to determine which values to include
Creates a new sequence using a callable to determine which values to include.
callback
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.
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.
示例 #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;
}));
?>以上示例的输出类似于：
object(Ds\Vector)#3 (2) {
[0]=>
int(2)
[1]=>
int(4)
}
示例 #2 Ds\Sequence::filter() example without a callback function
<?php
$sequence = new \Ds\Vector([0, 1, 'a', true, false]);
var_dump($sequence->filter());
?>以上示例的输出类似于：
object(Ds\Vector)#2 (3) {
[0]=>
int(1)
[1]=>
string(1) "a"
[2]=>
bool(true)
}