ios NSRegularExpression trouble - regex

Question

I'm trying to do a basic regular expression in xcode and it's not cooperating.
NSString *urlString = #"http://www.youtube.com/v/3uyaO745g0s?fs=1&hl=en_US";
NSError *error = nil;
NSRegularExpression *regex = [NSRegularExpression regularExpressionWithPattern:#"/.*?v=(.*)&.*/" options:NSRegularExpressionCaseInsensitive error:&error];
NSTextCheckingResult *fmis = [regex firstMatchInString:urlString options:0 range:NSMakeRange(0, [urlString length])];
if(fmis) {
NSRange match = [fmis range];
NSLog(#"%i", match.location);
}
essentially, I'm just trying to suck 3uyaO745g0s out of the urlString. I assume a regular expression is the best way? Thanks for looking my question.
** EDIT **
sometimes the url will look like this: http://www.youtube.com/watch?v=3uya0746g0s and I have to capture the vid from that as well.

Answer 1

I think it's much easier to create an NSURL object and let it do its magic for you:
NSString *urlString = #"http://www.youtube.com/v/3uyaO745g0s?fs=1&hl=en_US";
NSURL *url = [NSURL URLWithString:urlString];
// Since you're targeting the last component of the url
NSString *myMatch = [url lastPathComponent]; //=> 3uyaO745g0s
You can find more on how to access various parts of an NSURL object here

Answer 2

There are many types of Youtube URLs.
Maybe you can try this
NSString *urlString = #"http://www.youtube.com/v/3uyaO745g0s?fs=1&hl=en_US";
NSString *regEx = #"[a-zA-Z0-9\\-\\_]{11}";
NSRange idRange = [urlString rangeOfString:regEx options:NSRegularExpressionSearch];
NSString *youtubeID = [urlString substringWithRange:idRange];
I found this regular expression here. And you don't have to use NSRegularExpression for simple search:)
I think this is pretty good solution but if you want more reliable result, then try another regular expression in that answer.