when to use ===

[nozom]

I've been ignoring this for a while but i'm sure there is a reason i sometimes see

if ($i === $a)
 {...

instead of

if ($i == $a)
 {...

Whats the reason behind it?

ta,
nozom

[dalecosp]

Check the [man]manual[/man] section on arithmetic operators.

Specifically, PHP is a "loosely typed" language, and doesn't care to compare variable types unless you specifically ask it to.

"===" compares not only the value but also the type.

[laserlight]

hmm... actually, you should check for logical/comparison operators, not for arithmetic operators.

[drawmack]

As for when I use which

let's say I had a function like this

<?php
function count_letters($string,$letter) {
    if(strlen($string) < 1) {return FALSE;}
    elseif(strlen($letter) > 1) {return FALSE;}

$i=0;
$temp = 0;
while(strpos($string,$letter,$temp) !== FALSE) {
    $temp = strpos($string,$letter,$temp) + 1;
    $i++;
} //end while
return $i;
} //end count_letters

First you'll notice that the while condition uses !== this is because strpos returns FALSE if it is not found but would return 0 if it is the first character, so I need to differentiate between not found and found in the first position.

Secondly notice that if the letter is not found I return 0 but if the parameters are wrong I return FALSE. So if I were checking if this function ran properly I would have to use === or !== to also check the type of the return value.

[nozom]

and all becomes clear ;-)

Thankyou everyone, great stuff!

nozom