php 可以将方法用作 array_map 函数吗
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Can a method be used as an array_map function
提问by allyourcode
I want to do something like this:
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
but the first argument to array_map is supposed to be the name of the function. I want to avoid writing a wrapper function around $instance->fun, but it doesn't seem like that's possible. Is that true?
但是 array_map 的第一个参数应该是函数的名称。我想避免围绕 $instance->fun 编写包装函数，但这似乎不可能。真的吗？
回答by Jani Hartikainen
Yes, you can have callbacks to methods, like this:
是的，您可以对方法进行回调，如下所示：
array_map(array($instance, 'fun'), $ar)
see the callback typein PHP's manual for more info
有关更多信息，请参阅PHP 手册中的回调类型
回答by Metronom
You can also use
你也可以使用
array_map('Class::method', $array)
syntax.
句法。
回答by lijinma
Actually, you need to know the definition of Callback, please kindly refer to the following code:
其实你需要知道Callback的定义，请参考以下代码：
<?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
?>
