PHP Array Function array_map () Notes

PHP Array Function array_map () Notes

Definition and usage

The array_map () function returns the array after the User-Defined Function is applied. The number of parameters accepted by the callback function should be the same as the number of arrays passed to the array_map () function.

Syntax

Array_map (function, array1, array2, array3 ...)

Parameters	Description
Function	Required. The name of the User-Defined Function, or null.
Array1	Required. Specified array.
Array2	Optional. Specified array.
Array3	Optional. Specified array.

Example 1

<?phpfunction myfunction($v) {if ($v === "Dog") {return "Fido";}return $v;}$a = array("Horse", "Dog", "Cat");print_r(array_map("myfunction", $a));?>

Output:

Array ([0] => Horse [1] => Fido [2] => Cat)

Example 2

Use multiple parameters:

<?phpfunction myfunction($v1, $v2) {if ($v1 === $v2) {return "same";}return "different";}$a1 = array("Horse", "Dog", "Cat");$a2 = array("Cow", "Dog", "Rat");print_r(array_map("myfunction", $a1, $a2));?>

Output:

Array ([0] => different [1] => same [2] => different)

Example 3

See when the custom function name is set to null:

<?php$a1 = array("Dog", "Cat");$a2 = array("Puppy", "Kitten");print_r(array_map(null, $a1, $a2));?>

Output:

Array (
[0] => Array ([0] => Dog [1] => Puppy)
[1] => Array ([0] => Cat [1] => Kitten)
)

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