Why would this if/else statement not work?

[Ixzion]

I was working with something involving !=, which always manages to find some way to trip me up, but I'm finding this one odd and I'm wondering if one of you fine people can shed some light on it. This was the setup:

if (($thing != 0) && ($thing != "")) {echo "Hello";}

If $thing = 1, then this works.If $thing = 'taco', this does not work. But if $thing == 'taco', then obviously it doesn't equate to 0. The way I figured out a solution to this was by changing it to this:

if (($thing != "0") && ($thing != "")) {echo "Hello";}

With the 0 in quotation marks. Why did I have to do that? My guess is that if $thing is a string and my comparison is looking for an integer, that it borks it up somehow. But someone who knows would be nice.

[Don E]

The reason why the 0 in quotation marks works is because you're basically saying: if the string 'taco' is not equal to the string '0', which turns out to be true because they are not equal strings. If you're looking to check if a variable contains a value in an if statement, you can do something like the following:

$thing = "taco"; if (($thing != NULL) && ($thing != "")){	 echo "Hello";}

or...

$thing = "taco"; if (($thing != FALSE) && ($thing != "")){	 echo "Hello";}

or..

$thing = "taco"; if (($thing !== 0) && ($thing != "")) // True if they are not of same type which they aren't, $thing is string, 0 is integer.{	 echo "Hello";}

or with the empty() function..

$thing = "taco"; if ((!empty($thing)) && ($thing != "")) {     echo "Hello";}

Edited December 19, 2012 by Don E

[Ixzion]

Thanks for the explanation! Cheers!

[justsomeguy]

it borks it up somehow

Interesting choice of words. Judge Robert Bork just died at the age of 85, he's the reason we have that term. He got screwed by the Senate during his confirmation hearings for the Supreme Court in 1987, and since then people who get rejected or have problems unfairly are said to get "borked".

[wacsyweezy]

It is better to use the empty() function of PHP to check for empty variable than using the !="";

[justsomeguy]

The empty function will check for any value considered to be false. Those values are listed in the manual: http://www.php.net/manual/en/function.empty.php

[Ixzion]

Thanks guys. Valuable advice.