array_walk
时间: 2023-10-23 10:12:38 浏览: 68
好的,你的问题是关于 PHP 中的 array_walk 函数的吗?
array_walk 函数是 PHP 中用于对数组中的每个元素应用用户自定义函数的函数。它可以遍历数组中的每个元素,并将其传递给用户自定义函数进行处理。
例如,以下代码将数组 $arr 中的每个元素都转换为大写字母:
```
function convertToUpper(&$value, $key) {
$value = strtoupper($value);
}
$arr = array("apple", "banana", "orange");
array_walk($arr, "convertToUpper");
print_r($arr);
```
输出结果为:
```
Array
(
[0] => APPLE
[1] => BANANA
[2] => ORANGE
)
```
相关问题
php array_walk_recursive
The `array_walk_recursive` function in PHP is used to apply a user-defined function to each element of an array recursively. This means that it will traverse through all nested arrays and apply the function to each element.
Syntax:
```
array_walk_recursive(array $array, callable $function [, mixed $userdata = NULL ])
```
Parameters:
- `$array` - Required. Specifies the array to be walked recursively.
- `$function` - Required. Specifies the user-defined function to be applied to each element of the array recursively.
- `$userdata` - Optional. Specifies additional user-defined data to be passed to the function.
Return Value:
The `array_walk_recursive` function does not return anything. It modifies the original array by applying the user-defined function to each element.
Example:
```
function addOne(&$value, $key) {
$value += 1;
}
$array = array(1, 2, array(3, 4, array(5, 6)));
array_walk_recursive($array, 'addOne');
print_r($array);
```
Output:
```
Array
(
[0] => 2
[1] => 3
[2] => Array
(
[0] => 4
[1] => 5
[2] => Array
(
[0] => 6
[1] => 7
)
)
)
```
In this example, the `addOne` function is defined to add 1 to each element. The `array_walk_recursive` function is then used to apply this function to each element of the array recursively. The output shows that each element has been incremented by 1.
php php array_walk_recursive 举例 解释
array_walk_recursive() 函数是 PHP 中用于遍历多维数组的函数。该函数可以在数组的每个元素上执行用户自定义的回调函数。
以下是一个使用 array_walk_recursive() 的示例:
```php
$fruits = array(
"apple" => array("green", "red"),
"banana" => array("yellow"),
"orange" => array("orange")
);
function change_color(&$value, $key) {
if($key == 0) {
$value = "dark " . $value;
} else {
$value = "light " . $value;
}
}
array_walk_recursive($fruits, "change_color");
print_r($fruits);
```
上述代码会输出以下结果:
```
Array
(
[apple] => Array
(
[0] => dark green
[1] => light red
)
[banana] => Array
(
[0] => light yellow
)
[orange] => Array
(
[0] => light orange
)
)
```
在上述代码中,我们首先定义了一个多维数组 $fruits,其中每个元素都是一个颜色数组。然后我们定义了一个回调函数 change_color(),该函数会将每个颜色名称前面添加 "dark" 或 "light"。
最后,我们使用 array_walk_recursive() 函数对 $fruits 数组进行遍历,并将回调函数 change_color() 应用于每个元素。最终输出的结果是经过颜色修改后的 $fruits 数组。