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Fixed typo; rewrote most of docs; see also foreach() and call_user_func_array().

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git-svn-id: https://svn.php.net/repository/phpdoc/en/trunk@100035 c90b9560-bf6c-de11-be94-00142212c4b1
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Philip Olson 2002-10-17 11:25:32 +00:00
parent 891e8eb600
commit 9dea6b1a31
1 changed files with 50 additions and 41 deletions
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91
reference/array/functions/array-walk.xml
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@ -1,5 +1,5 @@
<?xml version="1.0" encoding="iso-8859-1"?>
<!-- $Revision: 1.4 $ -->
<!-- $Revision: 1.5 $ -->
<!-- splitted from ./en/functions/array.xml, last change in rev 1.2 -->
<refentry id="function.array-walk">
<refnamediv>
@ -17,62 +17,68 @@
<methodparam choice="opt"><type>mixed</type><parameter>userdata</parameter></methodparam>
</methodsynopsis>
<simpara>
Applies the user-defined function named by <parameter>func</parameter>
to each element of <parameter>array</parameter>.
<parameter>func</parameter> will be passed array value as the
first parameter and array key as the second parameter. If
<parameter>userdata</parameter> is supplied, it will be passed as
the third parameter to the user function. <parameter>func</parameter>
must be a user-defined function, and can't be a native PHP function.
Thus, you can't use <function>array_walk</function> straight with
<function>str2lower</function>, you must build a user-defined function
with it first, and pass this function as argument.
Applies the user-defined function <parameter>func</parameter> to each
element of the <parameter>array</parameter> array. Typically,
<parameter>func</parameter> takes on two parameters.
The <parameter>array</parameter> parameter's value being the first, and
the key/index second. If the optional <parameter>userdata</parameter>
parameter is supplied, it will be passed as the third parameter to
function <parameter>func</parameter>.
</simpara>
<simpara>
<parameter>func</parameter> must be a user-defined function, not a
built-in PHP function such as <function>strtolower</function> or
<function>stripslashes</function>. The user-defined function can
use built-in PHP functions.
</simpara>
&note.func-callback;
<simpara>
If <parameter>func</parameter> requires more than two or three
arguments, depending on <parameter>userdata</parameter>, a
warning will be generated each time
<function>array_walk</function> calls
<parameter>func</parameter>. These warnings may be suppressed by
prepending the '@' sign to the <function>array_walk</function>
call, or by using <function>error_reporting</function>.
If function <parameter>func</parameter> requires more parameters than
given to it, an error of level <link linkend="errorfunc.constants">
E_WARNING</link> will be generated each time <function>array_walk</function>
calls <parameter>func</parameter>. These warnings may be suppressed by
prepending the PHP error operator
<link linkend="language.operators.errorcontrol">@</link> to the
<function>array_walk</function> call, or by using
<function>error_reporting</function>.
</simpara>
<note>
<para>
If <parameter>func</parameter> needs to be working with the
actual values of the array, specify that the first parameter of
<parameter>func</parameter> should be passed by reference. Then
any changes made to those elements will be made in the array
itself.
</para>
<para>
Modifying the array from inside <parameter>func</parameter>
may cause unpredictable behavior.
actual values of the array, specify the first parameter of
<parameter>func</parameter> as a
<link linkend="language.references">reference</link>. Then,
any changes made to those elements will be made in the
original array itself.
</para>
</note>
<note>
<para>
Passing the key and userdata to <parameter>func</parameter> was
added in 4.0.
</para>
<para>
In PHP 4 <function>reset</function> needs to be called as
necessary since <function>array_walk</function> does not reset
the array by default.
</para>
<para>
Users may not change the array itself from the callback
function. e.g. Add/delete element, unset the array that
<function>array_walk</function> is applied to. If the array is
changed, the behavior of this function is undefined.
added in 4.0.0
</para>
</note>
<para>
<function>array_walk</function> is not affected by the internal
array pointer of <parameter>array</parameter>. <function>
array_walk</function> will walk through the entire array
regardless of pointer position. To reset the pointer, use
<function>reset</function>. In PHP 3,
<function>array_walk</function> resets the pointer.
</para>
<para>
Users may not change the array itself from the callback
function. e.g. Add/delete elements, unset elements, etc. If
the array that <function>array_walk</function> is applied to
is changed, the behavior of this function is undefined, and
unpredictable.
</para>
<para>
<example>
<title><function>array_walk</function> example</title>
<programlisting role="php">
<![CDATA[
<?php
$fruits = array ("d"=>"lemon", "a"=>"orange", "b"=>"banana", "c"=>"apple");
function test_alter (&$item1, $key, $prefix) {
@ -82,13 +88,15 @@ function test_alter (&$item1, $key, $prefix) {
function test_print ($item2, $key) {
echo "$key. $item2<br>\n";
}
echo "Before ...:\n";
array_walk ($fruits, 'test_print');
reset ($fruits);
array_walk ($fruits, 'test_alter', 'fruit');
echo "... and after:\n";
reset ($fruits);
array_walk ($fruits, 'test_print');
?>
]]>
</programlisting>
<para>
@ -111,7 +119,8 @@ c. fruit: apple
</example>
</para>
<simpara>
See also <function>each</function> and <function>list</function>.
See also <function>list</function>, <link linkend="control-structures.foreach">foreach</link>,
<function>each</function>, and <function>call_user_func_array</function>.
</simpara>
</refsect1>
</refentry>