你能在 PHP 数组中存储一个函数吗? [英] Can you store a function in a PHP array?

问题描述

例如:

$functions = array(
  'function1' => function($echo) { echo $echo; }
);

这可能吗?最好的选择是什么?

Is this possible? What's the best alternative?

推荐答案

推荐的方法是使用 匿名函数:

$functions = [
  'function1' => function ($echo) {
        echo $echo;
   }
];

如果你想存储一个已经声明的函数，那么你可以简单地通过名称作为字符串来引用它:

If you want to store a function that has already been declared then you can simply refer to it by name as a string:

function do_echo($echo) {
    echo $echo;
}

$functions = [
  'function1' => 'do_echo'
];

在古代版本的 PHP (<5.3) 中不支持匿名函数，您可能需要求助于使用 create_function(自 PHP 7.2 起已弃用):

In ancient versions of PHP (<5.3) anonymous functions are not supported and you may need to resort to using create_function (deprecated since PHP 7.2):

$functions = array(
  'function1' => create_function('$echo', 'echo $echo;')
);

所有这些方法都列在 下的文档中callable 伪类型.

All of these methods are listed in the documentation under the callable pseudo-type.

无论您选择哪种方式，都可以直接调用该函数 (PHP ≥5.4) 或使用 call_user_func/call_user_func_array:

Whichever you choose, the function can either be called directly (PHP ≥5.4) or with call_user_func/call_user_func_array:

$functions['function1']('Hello world!');

call_user_func($functions['function1'], 'Hello world!');

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