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PHP array_walk() Function

PHP Array Reference Complete PHP Array Reference

Definition and Usage

The array_walk() function runs each array element in a user-made function. The array's keys and values are parameters in the function. Returns True or False

Syntax

array_walk(array,function,parameter...)

Parameter Description
array Required. Specifying an array
function Required. The name of the user-made function
parameter Optional. Specifies a parameter to the user-made function

Tips and Notes

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

Note: You can change an array element's value in the user-made function by specifying the first parameter as a reference: &$value. (See example 3)

Example 1

<?php
function myfunction($value,$key)
{
echo "The key $key has the value $value<br />";
}
$a=array("a"=>"Cat","b"=>"Dog","c"=>"Horse");
array_walk($a,"myfunction");
?>

The output of the code above will be:

The key a has the value Cat
The key b has the value Dog
The key c has the value Horse

Example 2

With a parameter:

<?php
function myfunction($value,$key,$p)
{
echo "$key $p $value<br />";
}
$a=array("a"=>"Cat","b"=>"Dog","c"=>"Horse");
array_walk($a,"myfunction","has the value");
?>

The output of the code above will be:

a has the value Cat
b has the value Dog
c has the value Horse

Example 3

Change an array element's value. (Notice the &$value)

<?php
function myfunction(&$value,$key)
{
$value="Bird";
}
$a=array("a"=>"Cat","b"=>"Dog","c"=>"Horse");
array_walk($a,"myfunction");
print_r($a);
?>

The output of the code above will be:

Array ( [a] => Bird [b] => Bird [c] => Bird )

PHP Array Reference Complete PHP Array Reference
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