(PHP 4, PHP 5)
array_walk — Apply a user function to every member of an array
Applies the user-defined function funcname to each
element of the array array.
array_walk() is not affected by the internal array
pointer of array. array_walk()
will walk through the entire array regardless of pointer position.
array
The input array.
funcname
Typically, funcname takes on two parameters.
The array parameter's value being the first, and
the key/index second.
Note:
If
funcnameneeds to be working with the actual values of the array, specify the first parameter offuncnameas a reference. Then, any changes made to those elements will be made in the original array itself.
Note:
Many internal functions (for example strtolower()) will throw a warning if more than the expected number of argument are passed in and are not usable directly as
funcname.
Only the values of the array may potentially be
changed; its structure cannot be altered, i.e., the programmer cannot
add, unset or reorder elements. If the callback does not respect this
requirement, the behavior of this function is undefined, and
unpredictable.
userdata
If the optional userdata parameter is supplied,
it will be passed as the third parameter to the callback
funcname.
Returns TRUE on success or FALSE on failure.
If function funcname requires more parameters than
given to it, an error of level
E_WARNING will be generated each time array_walk()
calls funcname. These warnings may be suppressed by
prepending the PHP error operator
@ to the
array_walk() call, or by using
error_reporting().
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 above example will output:
Before ...: d. lemon a. orange b. banana c. apple ... and after: d. fruit: lemon a. fruit: orange b. fruit: banana c. fruit: apple