w3resource

PHP: array_walk() function

PHP: Apply a user supplied function to every member of an array

The array_walk() function apply a user defined function to every element of an array. The user-defined function takes array's values and keys as parameters.

Note: array_walk() is not affected by the internal array pointer of the array. array_walk() will walk through the entire array regardless of pointer position.

Version:

(PHP 4 and above)

Syntax:

array_walk(input_array, user_function, user_data)

Parameters:

Name Description Required /
Optional		 Type
input_array The input array. Required Array
user_function The name of the userdefined function. Required
-
user_data Additional parameter. If it is supplied, it will be passed as the third parameter to the user_function. Optional Mixed*

*Mixed: Mixed indicates that a parameter may accept multiple (but not necessarily all) types.

Return value

TRUE on success or FALSE on failure.

Value Type: Boolean.

Example:

<?php
function w3rfunction($value,$key)
{
echo "w3resource $key has $value<br />";
}
$tutorials=array("tutorial1"=>"php","tutorial2"=>"xml","tutorial3"=>"javascript");
array_walk($tutorials,"w3rfunction");
?>

Output:

w3resource tutorial1 has php
w3resource tutorial2 has xml
w3resource   tutorial3 has javascript

View the example in the browser

Practice here online:

See also

PHP Function Reference

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Next: arsort



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PHP: Tips of the Day

Filters the collection using the given callback

Example:

<?php
function tips_reject($items, $func)
{
  return array_values(array_diff($items, array_filter($items, $func)));
}

print_r(tips_reject(['Apple', 'Pear', 'Kiwi', 'Banana'], function ($item) {
  return strlen($item) > 4;
}));
?>

Output:

Array
(
    [0] => Pear
    [1] => Kiwi
)