[steveo]

This may sound stupid, but what does the following snippet of code actually mean/do?

PHP Code:

if(!$a=="") 

I've experimented and I know how it works, but I'm not sure if I'm right about what it does, could anyone just clarify what it does?

[Acecool]

if !empty() means, if not empty
if !isset() means if is not set.

[<?Wille?>]

Originally Posted by steveo

This may sound stupid, but what does the following snippet of code actually mean/do?

PHP Code:

if(!$a=="") 

I've experimented and I know how it works, but I'm not sure if I'm right about what it does, could anyone just clarify what it does?

if variable a is not equal to ""
could also be written if ($a != "")

E: thats what i would say.. not sure tho

[steveo]

Thought so,
thanks.

[Acecool]

Thats it Wille.

Could also be written:

If a is not empty
if !empty($a)

[1jetsam]

Code:

if (!$a == "") {

}

is the same as:

Code:

if (!$a == NULL) {

}

or

Code:

if (!($a)) {

}

Breaking it up. This part: $a=="" means If variable 'a' is equal to nothing (NULL), then...
and the ! means the opposite: If varaible 'a' does not equal nothing.
The last example I provided just means, (which is just another way to think of it): If variable 'a' is not set (if it is not assigned to anything...if it is equal to nothing, NULL)...

[okki]

$a=""
means variable a is equal to an empty string, which is different from $a=NULL

!$a="" would be: $a is not an empty string or !empty($a)
wehre
!$a=NULL would be: $a is not NULL or !isset($a)

Correct me if I'm wrong but there is a difference and that difference has something to do with memory allocation.

Grz.

[<?Wille?>]

Originally Posted by okki

$a=""
means variable a is equal to an empty string, which is different from $a=NULL

!$a="" would be: $a is not an empty string or !empty($a)
wehre
!$a=NULL would be: $a is not NULL or !isset($a)

Correct me if I'm wrong but there is a difference and that difference has something to do with memory allocation.

Grz.

exactly my toughts

[Sabu]

Originally Posted by <?Wille?>

exactly my toughts

Actually, don't ever use any of those first structures because they lack the double equals ==, therefore causing them to be treated as an instruction and always return positive (or negative if you use the exclamation mark)

[Acecool]

if ($a = "")
{
echo 'The variable \$a was set to ""';
}
..

Thats what happens if you use one equals sign..

If $x = this_condition
so, if $x was successfully set to the conditions value...