design flaw in strpos()?

Anon

If strpos() does not find the string, it returns false (0). However, if it finds the "needle" at the beginning of the "haystack" it returns...0. Oops?

strpos('string', 'str') == false (!?)

It took me a while to find out this is why strpos() wasn't finding my strings correctly. The server has, as I recall, PHP 3.0.9.

Anon

I know, I had the same prob once. If strpos could find the needle, it returns "", otherwise it returns "0". So I guess you could check like this:

$pos = strpos($haystack, $needle);
if ($pos == "0") {
   // Blah blah bleh
}

A safer way that I often use is this:

// Put any one character before the $haystack string
$pos = strpos("a" . $haystack, $needle);
if ($pos == "1") {
   echo "Found at position 1.";
}

Now this returns false when not found, otherwise the position + 1. Just $pos-- for the real position.

Greetz,

Vincent Driessen
Venlo, The Netherlands

Anon

Actually the support folks at php.net were kind enough to point to a better solution. I had contacted them because your first solution (if ($pos == "0")) apparently works in 3.x but not 4.01pl2 (still working out all the details). The end around is to use strict type checking:

if ($pos === 0) {
(...)

The other way, which is really what I meant to do 🙂, is to add a character and test for ($pos > 0).

recompiler

I just do it like this

$position = $stag = $etag= -1; #start searching for tag at this position

 $stag = strpos($val, ($tag[1]), 0);      #find opened tag
 $etag = strpos($val, ($tag[3]), 0);      #find closed tags

 if($etag=="")
   $etag=-1;

 if($stag=="")
   $stag=-1;