PHP Programming Specification Variable assignment method

Variable Assignment

<?php

$a = 1;
$b = 1;
$c = 2;
$d = 2;
if ($a = = $b && $c = = $d) die (' Error ');//Error

if ($a = = $b) && ($c = = $d)) die (' yes ');

?>

Do not use the inline (embedded) assignment operator to try to increase the efficiency of the runtime, which is the work of the compiler. For example:
$d = ($a = $b + $c) + $r; Error

should be written
$a = $b + $c;
$d = $a + $r;

Avoid assigning multiple variables to the same value in one statement. It's hard to read. For example:
$fooBar. Fchar = $barFoo. Lchar = ' C '; Error

Do not use assignment operators where they are easily confused with the equality relational operator. For example:
if ($c + + = $d + +) {//Error
...
}

should be written
if ($c + + = $d + +)!= 0) {
...
}