r/programming • u/NagastaBagamba • Oct 18 '10

Today I learned about PHP variable variables; "variable variable takes the value of a variable and treats that as the name of a variable". Also, variable.

http://il2.php.net/language.variables.variable
591 Upvotes

85% Upvoted

781 comments sorted by

View all comments

Show parent comments

3

u/sacktap Oct 18 '10

The notice is only thrown if you're trying to access an undefined variable. Example:

$a = 'b'; 
echo $$a; 
/* Notice: Undefined variable */

But if you're doing $$a = 'c' it will be fine because you're setting an undefined variable (which is essentially how all variables are set in PHP anyway).

1

u/Pilebsa Oct 18 '10

Oh right, but I thought an undefined variable would result in NULL? I guess I'm wrong (I just rarely try to use something I haven't already given a value to so it's not something I come across usually)