Developer. Gamer. Yo-Yo Thrower.

PHP Variable variables

Gah! I was reading about variable variables the other night!! Damn my memory!

I just bombed an interview question asking what does this line do:

$$foo = "x";

I knew I had seen it, and I knew it was a newer feature for PHP5.
It’s to do with PHPs variable variables feature. In a nutshell, it allows you to set dynamic variable names.

$x = 9;
$foo = "x";
echo $$foo;
//prints 9

So the correct answer to “What does that statement do?” would have been “refers to variable $x”. That’s one feature of PHP I won’t soon forget.

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