PHP < => spacecraft operator (combined comparator)

PHP <=> Spaceship operator （ Combination comparator ）

PHP 7 The new spacecraft operator （ Combination comparator ） Used to compare two expressions $a and $b, If $a Less than 、 Equal to or greater than $b when , It returns separately -1、0 or 1.

Specific understanding ：

1、 When the variable or expression on the left is larger than that on the right , return  1

2、 When the variable or expression on the left is equal to the variable or expression on the right , return  0

3、 When the variable or expression on the left is smaller than that on the right , return  -1

PHP Spaceship operator Examples of use

1、 Integer comparison

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