empty variables?

[TeddyKiller]

I probs know the answer to this, I just need reassuring that I've got it right.

 

If I have a variable..

$user = '';

 

This can be used as.. if(empty($user)) { }

Though if that variable isn't defined.. would the same line work?

If not.. would doing it as if(!$user) { } work?

[Ken2k7]

Yes, empty will work.

 

The !(boolean) $user would result in true. Basically speaking, empty($var) and (boolean) $var are opposites.

[dirkers]

empty() will have covered if the variable is an empty string or undefined. Don't use if (!$user) { }. However, be careful with empty() because it also returns TRUE for the integer 0 and string "0". For more details on empty(), take a look at the empty() PHP Manual page. Depending on your scenario, you might want to look at isset().

 

-D

[Ken2k7]

dirkers, could you please explain why we should not use if (!$user) { }?

[TeddyKiller]

if(empty($user)) works fine. Although.. same as what Ken2k7 ^^

[DavidAM]

dirkers is correct.  The OP was asking about undefined variables.  If you use if(!$user) and the variable is not defined, PHP will throw an error. 

[Ken2k7]

dirkers is correct.  The OP was asking about undefined variables.  If you use if(!$user) and the variable is not defined, PHP will throw an error. 

It'll throw a notice, but not really an error.