php静态函数 [英] php static function

问题描述

我有一个关于php中的静态函数的问题。

I have a question regarding static function in php.

我们假设我有一个类

class test {
    public function sayHi() {
        echo 'hi';
    }
}

：sayHi（）; 它没有问题。

if I do test::sayHi(); it works without a problem.

class test {
    public static function sayHi() {
        echo 'hi';
    }
}

test :: sayHi ）;

test::sayHi(); works as well.

第一类和第二类之间的区别是什么？

What are the differences between first class and second class?

一个静态函数有什么特别之处？

What is special about a static function?

推荐答案

在第一个类中， sayHi ）实际上是一个作为静态方法调用的实例方法，你逃避它，因为 sayHi（）从不引用 $ this 。

In the first class, sayHi() is actually an instance method which you are calling as a static method and you get away with it because sayHi() never refers to $this.

静态函数与类关联，而不是类的实例。因此， $ this 不能从静态上下文（ $ this 不指向任何对象）。

Static functions are associated with the class, not an instance of the class. As such, $this is not available from a static context ($this isn't pointing to any object).

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