方法可以用作 array_map 函数吗

Question

我想做这样的事情：

class Cls {
  function fun($php) {
    return 'The rain in Spain.';
  }
}

$ar = array(1,2,3);
$instance = new Cls();
print_r(array_map('$instance->fun', $ar));
               // ^ this won't work

但是 array_map 的第一个参数应该是函数的名称。 我想避免在 $instance->fun 周围编写包装函数，但这似乎不可能。 真的吗？

Answer 1

它对我有用如下

<?php
class ExcelAutoFilterController extends Controller
{
    public function transpose($value):array
        {
            return [$value];
        }

        public function generateExcelDropdownDownload($file = 'helloWorld.xlsx')
        {

            $countries = [0 => "Algeria"1 => "Angola"2 => "Benin"3 => "Botswana"4 => "Burkina"5 => "Burundi"6 => "Cameroon"7 => "Cape Verde"8 => "Central African Republic"9 => "Chad"10 => "Comoros"11 => "Congo"12 => "Congo, Democratic Republic of"13 => "Djibouti"14 => "Egypt"15 => "Equatorial Guinea"16 => "Eritrea"17 => "Ethiopia"18 => "Gabon"19 => "Gambia"20 => "Ghana"21 => "Guinea"22 => "Guinea-Bissau"23 => "Ivory Coast"24 => "Kenya"25 => "Lesotho"26 => "Liberia"27 => "Libya"28 => "Madagascar"29 => "Malawi"30 => "Mali"31 => "Mauritania"32 => "Mauritius"];

            $countries = array_map('self::transpose', $countries);
        }
        

Answer 2

是的，您可以对方法进行回调，如下所示：

array_map(array($instance, 'fun'), $ar)

请参阅回调类型< PHP 手册中的 /a> 了解更多信息

Answer 3

您还可以使用

array_map('Class::method', $array) 

语法。

Answer 4

其实，你需要了解Callback的定义，请参考下面的代码：

<?php 

// An example callback function
function my_callback_function() {
    echo 'hello world!';
}

// An example callback method
class MyClass {
    static function myCallbackMethod() {
        echo 'Hello World!';
    }
}

$myArray = [1, 2, 3, 4];

// Type 1: Simple callback
array_map('my_callback_function', $myArray); 

// Type 2: Static class method call
array_map(array('MyClass', 'myCallbackMethod'), $myArray); 

// Type 3: Object method call
$obj = new MyClass();
array_map(array($obj, 'myCallbackMethod'), $myArray);

// Type 4: Static class method call (As of PHP 5.2.3)
array_map('MyClass::myCallbackMethod', $myArray);

// Type 5: Relative static class method call (As of PHP 5.3.0)
class A {
    public static function who() {
        echo "A\n";
    }
}

class B extends A {
    public static function who() {
        echo "B\n";
    }
}

array_map(array('B', 'parent::who'), $myArray); // A
?>

来自： http://php.net/manual/en/language.types.callable.php