The Ds\Sequence::apply() function is an inbuilt function in PHP which is used to updates all value of sequence by applying a callback function to each value.
Syntax:
void abstract public Ds\Sequence::apply ( callable $callback )
Parameter: This function accepts single parameter $callback which is used to apply to each value in the sequence.
Return value: This function does not return any parameters.
Below programs illustrate the Ds\Sequence::apply() function in PHP:
Program 1:
<?php   // Create new sequence $seq = new \Ds\Vector([10, 20, 30, 40, 50]);   // Use apply() function $seq->apply(function($val) {     return $val / 5; });   // Display result print_r($seq);   ?> |
Output:
Ds\Vector Object
(
[0] => 2
[1] => 4
[2] => 6
[3] => 8
[4] => 10
)
Program 2:
<?php   // Create new sequence $seq = new \Ds\Vector([2, 3, 5, 6, 8]);   // Use apply() function $seq->apply(function($val) {     return $val; });   // Display result var_dump($seq);   ?> |
Output:
object(Ds\Vector)#1 (5) {
[0]=>
int(2)
[1]=>
int(3)
[2]=>
int(5)
[3]=>
int(6)
[4]=>
int(8)
}
Reference: https://www.php.net/manual/en/ds-sequence.apply.php
