Question

Throughout much of the code I review, I often see things such as:

// $myvar could be anything

if (intval($myvar) > 0) {
  // do stuff
}

Or similarly:

if ($myvar != null && intval($myvar) > 0) {
  // do stuff
}

In an ongoing quest to produce more elegant and less-wasteful code, I am wondering if it is necessary to call intval(), for example, when performing a numeric comparison. My understanding from reading the documentation and from various responses here is that when a numeric comparison is asked for, it checks the type of the var and then performs either an integer cast or a string conversion depending on what it finds — or are these the same as far as PHP is concerned, operations-wise?

Based on that, it seems the least expensive way is to tell PHP to cast it directly as an integer, as such:

if ((int)$myvar > 0) {
  // do stuff
}

However, I almost never see it written that way. Am I missing anything? Does PHP automatically do this any time it seems a comparison operator?

I realize in 99.9% of situations it is sufficient to just perform the comparison and let PHP type juggle on its own, but I see this so often that either I am missing something or many others are!

Answer 1

You haven’t given a reason to cast at all:

$myvar > 0

will have the same effect. Either way, non-numeric strings can be coerced to 0 (this is one of PHP’s many strange design choices), and numeric strings are coerced to the number they represent. Thus after:

$myvar = "foo";

the following are identical (and false):

(int) $myvar > 0
$myvar > 0

Of course, casting to int may be useful in other situations. Another useful function is is_numeric, which checks for a number or numeric string.