PHP | Ds\Sequence apply() Function

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