The Ds\Sequence::map() function is an inbuilt function in PHP which returns the result after applying callback function to each value.
Syntax:
Ds\Sequence abstract public Ds\Sequence::map( $callback )
Parameter: This function accepts single parameter $callback. The callback apply on each value of sequence.
Return Value: This function returns the callback after applying on each value.
Below programs illustrate the Ds\Sequence::map() function in PHP:
Program 1:
<?php    // Create new sequence $seq = new \Ds\Vector( [4, 8, 12, 16] );   // Use map() function and display it var_dump($seq->map(function($val) {         return $val * 3; }));    ?> |
Output:
object(Ds\Vector)#3 (4) {
[0]=>
int(12)
[1]=>
int(24)
[2]=>
int(36)
[3]=>
int(48)
}
Program 2:
<?php    // Create new sequence $seq = new \Ds\Vector([12, 15, 18, 20]);   // Use map() function and display it var_dump($seq->map(function($val) {         return $val / 3; }));    ?> |
Output:
object(Ds\Vector)#3 (4) {
[0]=>
int(4)
[1]=>
int(5)
[2]=>
int(6)
[3]=>
float(6.6666666666667)
}
Reference: http://php.net/manual/en/ds-sequence.map.php
