Question

Lets take a variable called someInt which might have any numeric value. We need to check if it’s 0 or not.

if($someInt!=0) {
  // someInt is not 0, this is the most probable
} else {
  // someInt is 0.
}

//VS

if($someInt==0) {
  // highly unlikely... perform a jump
} else {

}

Which way is more optimal? Is there any difference (besides readability)?

Another sort of related thing I’m wondering: I have a habit of checking arrays if they any items this way:

if($myArray.length != 0) {

}
 // instead of
if($myArray.length > 0) {

}

Notice the ” != “. Since array.length can only be 0 or greater than 0, is the “!=” check more optimal?
I’m asking this because I’ve always done it this way in Visual Basic 6, it apparently worked faster there. What about other languages?

Answer 1

Most probable conditions should be at the top. This way, the parser skips the less probable cases, and you get an overly more optimized application.

Your second question is micro-optimization. I doubt it’ll make a difference one way or another in terms of performance.