trouble with srtpos()

[Antivirus]

Having trouble testing strpos below:

PHP Code:

$haystack = '11,20';
$needle = '1';

if (strpos($haystack, $needle) !== false) {
    return true;
}
else {
    return false;
} 


It's returning true because the '1' is within the haystack (11,20) however i only want it to return true if the needle is '11', not 1. Is there a different function i should be using to test for a numeric value within a string?
Thanks!

solved... needed to encapsulate the needle and haystack then do the strpos check, as follows:

PHP Code:

$haystack = '11,20'; 
$needle = '1'; 

if (strpos(",$haystack,", ",$needle,") !== false) { 
    return true; 
} 
else { 
    return false; 
}