PHP array_walk() Function
Topic: PHP Array ReferencePrev|Next
Description
The array_walk() function apply a user-defined function to every element of an array.
The following table summarizes the technical details of this function.
| Return Value: | Returns TRUE on success or FALSE on failure. |
|---|---|
| Version: | PHP 4+ |
Syntax
The basic syntax of the array_walk() function is given with:
array_walk(array, callback, userdata);
The following example shows the array_walk() function in action.
Example
Run this code »<?php
// Defining a callback function
function myFunction($value, $key){
echo "<p>$key for $value</p>";
}
// Sample array
$alphabets = array("a"=>"apple", "b"=>"ball", "c"=>"cat");
array_walk($alphabets, "myFunction");
?>Parameters
The array_walk() function accepts the following parameters.
| Parameter | Description |
|---|---|
| array | Required. Specifies the array to work on. |
| callback | Required. Specifies the name of the user-defined callback function. The callback function typically takes on two parameters — the array value being the first, and the key/index second. |
| userdata | Optional. Specifies a parameter to the user-defined callback function. It will be passed as the third parameter to the callback function. |
More Examples
Here're some more examples showing how array_walk() function actually works:
You can also pass an indexed array as parameter to this function, as shown here:
Example
Run this code »<?php
// Defining a callback function
function myFunction($value, $index){
echo "<p>The value at index $index is $value</p>";
}
// Sample array
$colors = array("red", "green", "blue", "orange");
array_walk($colors, "myFunction");
?>
