PHP variable assignment needs parentheses -

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i wrote code , found didn't work expected.

for example, following return false or throw exception, undefined variable: a:

if ($a = 12 && $a == 12) {     return true; } else {     return false; }

i fixed wrapping assignment in parentheses:

if (($a = 12) && $a == 12) {     return true; } else {     return false; }

it lucky guess. i'm wondering why parentheses needed , haven't found explains why.

that because of operator precedence. assignment operator = has lower precedence &&, without parenthesis doing following.

if ($a = (12 && $a == 12))

observe second $a not yet defined before assignment happens, because has evaluated before assignment can happen.


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