eregi to preg_match

Question

I am using a lib which uses

$pattern = "LIMIT[^\w]{1,}([0-9]{1,})([\,]{0,})([0-9]{0,})";
        $replacement = "";
        eregi($pattern, $query, $regs);
        $query = eregi_replace($pattern, $replacement, $query);

        if($regs[2])
            $query = str_ireplace("SELECT ", "SELECT TOP ".$regs[3]." ", $query);
        else
            {
            if($regs[1])
                $query  = str_ireplace("SELECT ", "SELECT TOP ".$regs[1]." ", $query);
            }

I change some part of the code to

$pattern = "/LIMIT[^\w]{1,}([0-9]{1,})([\,]{0,})([0-9]{0,})/i";
        $replacement = "";
        preg_match($pattern, $query, $regs);

But now I got error messages saying "Undefined offset: 2" and "Undefined offset: 1"

I think moving from eregi to preg_match should be easy...

Answer 1

There is no issue with preg_match or preg_replace or your regex.

You get this error when $query doesn't match at all (e.g. $query="SELECT foo FROM bar"). Then $regs is an empty array, so accessing $regs[2] results in an error since there are no elements in it to begin with.

I'd suggest using count($regs) to see whether to even do the $regs[2] thing.

$query="SELECT asdf FROM foo";
$pattern = "/LIMIT[^\w]{1,}([0-9]{1,})([\,]{0,})([0-9]{0,})/i";
$replacement = ""; 
preg_match($pattern, $query, $regs);
$query = preg_replace($pattern, $replacement, $query);


if( count($regs)>=0 ) {
    if($regs[2])
    // ... etc the #$egs[2] $regs[1] code here.
}