array_walk:
array_walk — 使用用户自定义函数对数组中的每个元素做回调处理
- 用户自定义的函数处理每一个元素
- 直接修改原数组,不会创建新的数组
可以传递额外的参数
Example #1 :
<?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’);
?>
//运行结果
Before …:
d. lemon
a. orange
b. banana
c. apple … and after:
d. fruit: lemon
a. fruit: orange
b. fruit: banana
c. fruit: apple
更多信息参考官方文档:http://php.net/manual/zh/function.array-walk.php
array_map
array_map — 为数组的每个元素应用回调函数
- 回调函数,应用到每个数组里的每个元素
- 可以处理多个数组,合并处理
- 返回新建的数组
- 传入 NULL 作为回调函数的名称,将创建多维数组
- 传入两个及以上的数组时,它们元素数量将会相同。因为回调函数会并行地处理相互对应的元素。 如果几个数组的元素数量不一致:空元素会扩展短那个数组,直到长度和最长的数组一样。
Example #1:
<?php
function cube($n)
{
return($n $n $n);
}
$a = array(1, 2, 3, 4, 5);
$b = array_map("cube", $a);
print_r($b);
?>
//运行结果
Array
(
[0] => 1
[1] => 8
[2] => 27
[3] => 64
[4] => 125
)
Example #2:
<?php
$func = function($value) {
return $value * 2;
};
print_r(array_map($func, range(1, 5)));
?>
//运行结果
Array
//运行结果
Array
(
[0] => 2
[1] => 4
[2] => 6
[3] => 8
[4] => 10
)
Example #3:
<?php
function show_Spanish($n, $m)
{
return(“The number $n is called $m in Spanish”);
}
function map_Spanish($n, $m)
{
return(array($n => $m));
}
$a = array(1, 2, 3, 4, 5);
$b = array("uno", "dos", "tres", "cuatro", "cinco");
$c = array_map("show_Spanish", $a, $b);
print_r($c);
$d = array_map("map_Spanish", $a , $b);
print_r($d);
?>
//运行结果
// printout of $c
Array
(
[0] => The number 1 is called uno in Spanish
[1] => The number 2 is called dos in Spanish
[2] => The number 3 is called tres in Spanish
[3] => The number 4 is called cuatro in Spanish
[4] => The number 5 is called cinco in Spanish
)
// printout of $d
Array
(
[0] => Array
(
[1] => uno
)
[1] => Array
(
[2] => dos
)
[2] => Array
(
[3] => tres
)
[3] => Array
(
[4] => cuatro
)
[4] => Array
(
[5] => cinco
)
更多信息参考官方文档:http://php.net/manual/zh/function.array-map.php
array_filter
- array_filter — 用回调函数过滤数组中的单元*
- 依次将 array 数组中的每个值传递到 callback 函数。如果 callback 函数返回 true,则 array 数组的当前值会被包含在返回的结果数组中。数组的键名保留不变。
- 如果没有提供 callback 函数, 将删除 array 中所有等值为 FALSE 的条目。
- ARRAY_FILTER_USE_KEY - callback接受键名作为的唯一参数,ARRAY_FILTER_USE_BOTH - callback同时接受键名和键值
Example 1:
<?php
function odd($var)
{
// returns whether the input integer is odd
return($var & 1);
}
function even($var)
{
// returns whether the input integer is even
return(!($var & 1));
}
$array1 = array("a"=>1, "b"=>2, "c"=>3, "d"=>4, "e"=>5);
$array2 = array(6, 7, 8, 9, 10, 11, 12);
echo "Odd :\n";
print_r(array_filter($array1, "odd"));
echo "Even:\n";
print_r(array_filter($array2, "even"));
?>