什么是< => (PHP 7中的"Spaceship"运算符)? [英] What is <=> (the 'Spaceship' Operator) in PHP 7?

问题描述

PHP 7(将于今年11月问世)将引入Spaceship(< =>)运算符.这是什么以及它如何工作?

PHP 7, which will come out in November this year will introduce the Spaceship (<=>) operator. What is it and how does it work?

_{此问题已经有答案在有关PHP运算符的一般参考问题中.}

_{This question already has an answer in our general reference question about PHP operators.}

推荐答案

<=>(太空飞船")运算符将提供组合比较，因为它将:

The <=> ("Spaceship") operator will offer combined comparison in that it will :

Return 0 if values on either side are equal
Return 1 if the value on the left is greater
Return -1 if the value on the right is greater

组合比较运算符使用的规则与PHP viz当前使用的比较运算符相同. <，<=，==，>=和>.那些来自Perl或Ruby编程背景的人可能已经熟悉为PHP7提议的这个新运算符.

The rules used by the combined comparison operator are the same as the currently used comparison operators by PHP viz. <, <=, ==, >= and >. Those who are from Perl or Ruby programming background may already be familiar with this new operator proposed for PHP7.

   //Comparing Integers

    echo 1 <=> 1; //output  0
    echo 3 <=> 4; //output -1
    echo 4 <=> 3; //output  1

    //String Comparison

    echo "x" <=> "x"; //output  0
    echo "x" <=> "y"; //output -1
    echo "y" <=> "x"; //output  1

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