PHP Variable Variables

Question

How does php handle something like this...

$blah = "Testing a variable"; 
$$blah = "test";

What would my new variable name be?

mmk k, so something like.. $blah = str_replace(" ", "_", $blah); would work sufficiently. — Dalton Conley, Dec 22 '10 at 17:41
$$ is one of the true evils/joys of PHP. combine with () for fun-ness! $$blah()(); — DampeS8N, Dec 22 '10 at 17:42
The one where you are coding for fun on your own? It is like coding in brainfuck. Joy. — DampeS8N, Dec 22 '10 at 18:18

score 9 · Answer 1 · answered Dec 22 '10 at 17:41

9

Everything you need to know about variable variables at http://www.php.net/manual/en/language.variables.variable.php, except for one thing: don't use them.

answered Dec 22 '10 at 17:41

Rafe Kettler

-1 for giving me a link to the manual, +1 for giving me some useful syntax advice. – Dalton Conley Dec 22 '10 at 17:48
1

@Stephen I know, right? The manual explains variable variables way better than most people here could. – Rafe Kettler Dec 22 '10 at 18:03

score 4 · Accepted Answer · answered Dec 22 '10 at 17:44

4

echo ${'Testing a variable'};

However, you don't want to do this in practice. It makes for unmaintainable, bug-prone code.

answered Dec 22 '10 at 17:44

webbiedave

score 1 · Answer 3 · answered Dec 22 '10 at 17:42

1

The variable $blah must contain a valid variable name.

answered Dec 22 '10 at 17:42

zsalzbank

score 0 · Answer 4 · answered Dec 22 '10 at 17:53

0

Not really an answer, but...

<?php 
function I_love_you()
{
    return "haha";
}

$haha = "HoHoHo";
$tom = "I_love_you";
$blah = "tom";

echo ${$$blah()};
?>

answered Dec 22 '10 at 17:53

DampeS8N

4 Answers4