array_walk()使用

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. lemona. orangeb. bananac. apple... and after:d. fruit: lemona. fruit: orangeb. fruit: bananac. 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';$myEmail = '[e-mail]';$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);'));