note 24480 added to function.strpos
| From: | csaba at alum dot mit dot edu | Date: | Sat, 17 Aug 2002 20:22:50 +0000 |
| Subject: | note 24480 added to function.strpos | ||
| Groups: | php.notes | ||
| Request: | Send a blank email to php-notes+get-35174@lists.php.net to get a copy of this message | ||
function nthPos ($haystack, $needle, $n=1) {
// finds the nth occurrence of any of $needle's characters in $haystack
// returns -1 if not found;
// $n negative => reverse search (starting from the end of $haystack)
// e.g. $str = "c:\\winapps\\morph\\photos\\Party\\Phoebe.jpg";
// substr($str, nthPos($str, "/\\:", -2)) => \Party\Phoebe.jpg
$pos = -1;
$size = strlen($haystack);
if ($reverse=($n<0)) { $n=-$n; $haystack = strrev($haystack); }
while ($n--) {
$bestNewPos = $size;
for ($i=strlen($needle)-1;$i>=0;$i--) {
$newPos = strpos($haystack, $needle[$i], $pos+1);
if ($newPos===false)
$needle = substr($needle,0,$i) . substr($needle,$i+1);
else $bestNewPos = min($bestNewPos,$newPos); }
if (($pos=$bestNewPos)==$size) return -1; }
return $reverse ? $size-1-$pos : $pos;
}
--
http://www.php.net/manual/en/function.strpos.php
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