PHP array_walk() Function

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# PHP array_walk() Function

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 )

Complete PHP Array Reference

From http://www.w3schools.com (Copyright Refsnes Data)