PHP : How to replace only the first occurrence in a string with str_replace

Oscar Sodani is a founder of Help2Go and owner of Help2Go Networks, an IT consulting firm in the Washington D.C. area. Oscar holds the CISSP certification as well as industry certifications from Microsoft, Cisco and Novell.

For instance, if I had the string "X. Xavier Reynolds", and I wanted to easily replace just the first occurence of the X character, I would have to jump through hoops to split the string first to replace only the first occurrence.

Luckily, I found a great snippet function posted by xinobit on the PHP documentation web site. I include it in almost all of my PHP apps:

function str_replace_count($search,$replace,$subject,$times) {
    $subject_original=$subject;
    $len=strlen($search);    
    $pos=0;
    for ($i=1;$i<=$times;$i++) {
        $pos=strpos($subject,$search,$pos);
        if($pos!==false) {                
            $subject=substr($subject_original,0,$pos);
            $subject.=$replace;
            $subject.=substr($subject_original,$pos+$len);
            $subject_original=$subject;
        } else {
            break;
        }
    }
    return($subject);
}

?> 

To use it, just call the function, like this:

$myString = "X. Xavier Reynolds";
print str_replace_count("X","A",$myString,1);
?>

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