(PHP 3 >= 3.0.3, PHP 4, PHP 5)
array_walk --
Apply a user function to every member of an array
Description
bool
array_walk ( array &array, callback funcname [, mixed userdata] )
Returns TRUE on success or FALSE on failure.
Applies the user-defined function funcname to each
element of the array array. Typically,
funcname 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 funcname.
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().
Note:
If funcname needs to be working with the
actual values of the array, specify the first parameter of
funcname 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 funcname 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.
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');
?>
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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
|
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See also array_walk_recursive(),
create_function(),
list(),
foreach,
each(),
call_user_func_array(), and
array_map(), and
information about the callback type.
