Order in conditional statements [duplicate]

Question

Possible Duplicate:
php false place in condition

I have noticed that a lot of PHP code uses conditional statements like CONST == VARIABLE. I grew up with the syntax always articulated in reverse. Is there a reason for this structure?

Example:

 // this is the way I see it most typically represented in PHP
 if ( false == $foobar ) { // do this }

 // this is the way I normally do it
 if ( $foobar == false ) { // do this }

Answer 1

This is to prevent a common typo between == and =, known as a yoda condition. Consider the following:

if( false = $foobar) {

This would result in an error, catching what would be considered a bug, since you cannot assign anything to false. On the contrary:

if( $foobar = false) { 

This is valid syntax, and is quite an easy mistake to make.

However, I typically prefer the if( $foobar == false) syntax, as unit tests should be able to catch these programmatic mistakes.

Answer 2

The way you normally do it is exactly how most programmers do it. The first example is called a yoda condition:

http://www.dodgycoder.net/2011/11/yoda-conditions-pokemon-exception.html

and is not the norm.