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PHP array_map() Function

< PHP Array Reference

Example

Send each value of an array to a function, multiply each value by itself, and return an array with the new values:

<?php
function myfunction($v)
{
  return($v*$v);
}

$a=array(1,2,3,4,5);
print_r(array_map("myfunction",$a));
?>
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Definition and Usage

The array_map() function sends each value of an array to a user-made function, and returns an array with new values, given by the user-made function.

Tip: You can assign one array to the function, or as many as you like.


Syntax

array_map(myfunction,array1,array2,array3...)

Parameter Description
myfunction Required. The name of the user-made function, or null
array1 Required. Specifies an array
array2 Optional. Specifies an array
array3 Optional. Specifies an array

Technical Details

Return Value: Returns an array containing the values of array1, after applying the user-made function to each one
PHP Version: 4.0.6+

More Examples

Example 1

Using a user-made function to change the values of an array:

<?php
function myfunction($v)
{
if ($v==="Dog")
  {
  return "Fido";
  }
return $v;
}

$a=array("Horse","Dog","Cat");
print_r(array_map("myfunction",$a));
?>
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Example 2

Using two arrays:

<?php
function 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));
?>
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Example 3

Change all letters of the array values to uppercase:

<?php
function myfunction($v)
{
$v=strtoupper($v);
  return $v;
}

$a=array("Animal" => "horse", "Type" => "mammal");
print_r(array_map("myfunction"
,$a));
?>
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Example 4

Assign null as the function name:

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

< PHP Array Reference