bool
array_walk (
array &$array ,
callable $callback [,
mixed $userdata = NULL ] )
将用户自定义函数 funcname 应用到 array 数组中的每个单元。 array_walk() 不会受到 array 内部数组指针的影响。array_walk() 会遍历整个数组而不管指针的位置。
array_walk($array, callback, userdata);
$array 输入的数组， callback($array的参数, 键名，$prefix) $userdata 将被作为第三个参数传递给 callback prefix
测试环境 7.0.1
<?php
$fruits = array(
"d" => "lemon", "a" => "orange", "b" => "banana", "c" => "apple")
;
function test_alter(
&$item1, $key, $prefix) //注意这里第一个是取地址符，$prefix 表示为前缀
{
$item1 = "$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";
var_dump(
$fruits)
;
array_walk(
$fruits, 'test_print')
;
Before ...:
d. lemon
a. orange
b. banana
c. apple
... and after:
d. fruit: lemon
a. fruit: orange
b. fruit: banana
c. fruit: apple
$fruits = array("1" => "lemon", "2" => "orange", "3" => "banana", "4" => "apple");
function test_print($item2, &$key)
{
++$key;
echo "$key. $item2<br />\n";
}
array_walk($fruits, 'test_print');
var_dump($fruits);exit; array(4) { [1]=> string(5) "lemon" [2]=> string(6) "orange" [3]=> string(6) "banana" [4]=> string(5) "apple" }
key值没有变化，说明，array_walk function中第二个方法中如果使用的key取地址符，key的值依然不变
Waring:
If the class is static: array_walk($array, array('self', 'walkFunction')); or array_walk($array, array('className', 'walkFunction')); Otherwise:
array_walk($array, array($this, 'walkFunction'));
array_walk 与匿名函数结合使用
function zip(
&$data, $glue=': ')
{
if(
!is_array(
$data)) {
throw new InvalidArgumentException(
'First parameter must be an array')
;
}
array_walk(
$data, function(
&$value, $key, $joinUsing) {
$value = $key . $joinUsing . $value;
}
, $glue)
;
}
$myName = 'Matthew Purdon';
$myEmail = 'matthew@example.com';
$from = "$myName <$myEmail>";
$headers[
'From']
= $from;
$headers[
'Reply-To']
= $from;
$headers[
'Return-path']
= "<$myEmail>";
$headers[
'X-Mailer']
= "PHP" . phpversion()
. "";
$headers[
'Content-Type']
= 'text/plain; charset="UTF-8"';
zip(
$headers)
;
$headers = implode(
"\n", $headers)
;
var_dump(
$headers)
;
exit;
$_POST['something'] = array_map(intval,$_POST['something']);
array_walk($ids, create_function('&$val', '$val = trim($val);'));
