Simple if structure always returns true when measuring strings

[CT Internet]

OK, this one is just plain weird.

I have coded php for years and have never seen this one before, yet it is very simple.

I am working on a component for Joomla, but that shouldn't really matter.

I am getting a variable from the request string with this Joomla function:

$var = mosGetParam( $_REQUEST, 'var', '0' );

All it does is set the var to 0 if it does not exist. I can see in my query string that the $var is set to 0 and when I echo the $var it also returns 0.

Now... here comes the scary part.

When I run an if structure on the $var it always returns true if what I compare it to is a string. Like this

if ($var == "somestring") {
  echo "var is somestring: ".$var;
}

But the echo is var is somestring: 0

If i do the following:

if ($var == "1") {
  echo "var is 1: ".$var;
}

It fails and does not validate, even though 1 is also a string in this comparison.

What is going on?

I have tried === but that is only for boolean - right? And I still want to know what is going on.

P.S. What I am really trying to do is check a check box if a certain value is "yes" but when the value id 0 and I check for "yes" it still returns true?!?!

[IP-Dope]

I have tried === but that is only for boolean - right?

same as == but this one only returns true if they're also the same type (array, object, bool, string etc.). But I don't know where it goes wrong to be honest...

Cheers,
Pepe

[kyberfabrikken]

if ($var == "somestring") {
  echo "var is somestring: ".$var;
} 

But the echo is var is somestring: 0

That can't be true. You must be doing something else. Doublecheck that this is the exact same code, as the code which is giving that result.

[jondolar]

I think in PHP...

if (0 == 0) // this is true
if (0 == "something") // this is true because "something" evaluates to a numeric 0

You can try this:
if ("xxx".$var == "xxxsomething")

that makes sure you convert $var to a string.
There's probably a better way like using ===