   #PHP Manual Array Functions array_values array

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                                  array_walk

   (PHP 3>= 3.0.3, PHP 4 )
   array_walk --  Apply a user function to every member of an array

Description

   bool array_walk ( array array, callback function [, mixed userdata])

   Returns TRUE on success or FALSE on failure.

   Applies the user-defined function function to each element of the
   array array. Typically, function takes on two parameters. The array
   parameter's value being the first, and the key/index second. If the
   optional userdata parameter is supplied, it will be passed as the
   third parameter to the callback function.

   If function function requires more parameters than given to it, an
   error of level E_WARNING will be generated each time array_walk()
   calls function. These warnings may be suppressed by prepending the PHP
   error operator @ to the array_walk() call, or by using
   error_reporting().

     Note: If function needs to be working with the actual values of the
     array, specify the first parameter of function as a reference.
     Then, any changes made to those elements will be made in the
     original array itself.

     Note: Passing the key and userdata to function was added in 4.0.0

   array_walk() is not affected by the internal array pointer of array.
   array_walk() will walk through the entire array regardless of pointer
   position. To reset the pointer, use reset(). In PHP 3, array_walk()
   resets the pointer.

   Users may not change the array itself from the callback function. e.g.
   Add/delete elements, unset elements, etc. If the array that
   array_walk() is applied to is changed, the behavior of this function
   is undefined, and unpredictable.

   Example 1. array_walk() example
   <?php
   $fruits = array("d" => "lemon", "a" => "orange", "b" => "banana", "c"
   => "apple");
   function test_alter(&$item1, $key, $prefix) {
       $item1 = "$prefix: $item1";
   }
   function test_print($item2, $key) {
       echo "$key. $item2<br />\n";
   }
   echo "Before ...:\n";
   array_walk($fruits, 'test_print');
   array_walk($fruits, 'test_alter', 'fruit');
   echo "... and after:\n";
   array_walk($fruits, 'test_print');
   ?>

   The printout of the program above will be:
   Before ...:
   d. lemon
   a. orange
   b. banana
   c. apple
   ... and after:
   d. fruit: lemon
   a. fruit: orange
   b. fruit: banana
   c. fruit: apple

   See also list(), foreach, each(), and call_user_func_array().
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