PHP array_walk() function

Example

Apply a user-defined function to each element in the array:

<?phpfunction myfunction($value,$key){echo "The key $key has the value $value<br>";}$a=array("a"=>"red","b"=>"green ","c"=>"blue");array_walk($a,"myfunction");?>

Definition and usage

The array_walk() function applies a user-defined function to each element in an array. In the function, the key name and key value of the array are parameters.

Note: You can change the value of an array element by specifying the first parameter in the user-defined function as a reference: &$value (see Example 2).

Tip: To operate on deeper arrays (one array within another array), use the array_walk_recursive() function.

grammar

 array_walk( array,myfunction,parameter... )

parameter	describe
array	Required. Specifies an array.
myfunction	Required. The name of the user-defined function.
parameter,...	Optional. Specifies the parameters of a user-defined function. You can set one or more parameters for the function.

technical details

Return value:	Returns TRUE if successful, otherwise returns FALSE.
PHP version:	4+

More examples

Example 1

With one parameter:

<?phpfunction myfunction($value,$key,$p){echo "$key $p $value<br>";}$a=array("a"=>"red","b"=>"green ","c"=>"blue");array_walk($a,"myfunction","has the value");?>

Example 2

Change the value of an array element (note the &$value):

<?phpfunction myfunction(&$value,$key){$value="yellow";}$a=array("a"=>"red","b"=>"green","c"=>" blue");array_walk($a,"myfunction");print_r($a);?>