A simple PHP Question

Izzmo · 10-01-2006, 06:01 PM

Okay, so I consider myself pretty technical with PHP, enough to make a portal-based graphics forum, my own script, like DeviantArt.

So, I've ALWAYS wondered this, where do you use the '===' at? (The 3 eqal signs in a row).

I've never came across it, ever, where I've had to use it..

So, can someone help me out?

Thanks.

StupidScript · 10-01-2006, 06:59 PM

That comparison operator means "identical to".

Here's a quick cheatsheat:

ASSIGNMENT OPERATOR:

Code:

=
Example: x = y;
Used to SET variable x equal in every way to variable y.

COMPARISON OPERATORS:

Code:

==
Example: if (x == y)
Used to COMPARE variable x to variable y.
If they are of the same VALUE, it matches

Code:

===
Example: if (x === y)
Used to COMPARE variable x to variable y.
If they are of the same VALUE and the same TYPE, it matches

Code:

!=
Example: if (x != y)
Used to COMPARE variable x to variable y.
If they are not of the same VALUE, it matches

Code:

!==
Example: if (x !== y)
Used to COMPARE variable x to variable y.
If they are not of the same VALUE and TYPE, it matches

I usually use the "identical" comparison operator when I am pulling an integer from a database. This is because any value greater than 0 can be interpreted as a boolean "true" value.

Code:

if (x == 1)
1 is an integer that will match if x has any value, even if x is a string.

Code:

if (x === 1)
1 is an integer that will match if x's value is 1 AND if x's type is "integer".

jwalsh · 10-01-2006, 09:05 PM

$x = "3";
$y = 3;

$x == $y will pass
$x === $y will fail because they are different types.

Now, if only PHP supported strict typing.

Litewebsite · 10-02-2006, 05:07 AM

You could also do type casting for your variables.

PHP Code:


		
			
$x = 1;

$y = '1';

$y = (int)$y; // type casting

Now both variables are integers and will match ===.

Izzmo · 10-02-2006, 12:33 PM

Ahah

Thanks!

All 3 of you have helped me out greatly. Thanks soo much!

(Now... off to code ASP .. dang)