iPhone: Parse Integer out of NSURL/NSString (NSScanner?) - iphone

Question

I am trying to build an iPhone App, where I read an RSS feed and have to parse out the id of an article from the URL.
The links provided by the RSS feed are like the following:
http://example.com/variable/path/components/352343/index.html
I need 352343.
So basically I need to search for at least one digit between slashes (path components could also contain digits). Regexp would be easy: "//(\d+)//". But how can I do it with NSScanner?
Thanks,
Ernesto

Answer 1

You can split your url string into parts separated by "/" and check if any part is a valid integer.
NSArray* components = [urlString componentsSeparatedByString:#"/"];
int myId;
for (NSString *comp in components){
NSScanner *scanner = [NSScanner scannerWithString:comp];
if ([scanner scanInt: &myId])
return myId;
}
or you can simply use NSString method:
int myId;
for (NSString *comp in components)
if (myId = [comp intValue]) // intValue returns 0 if comp is not an integer
return myId;

Answer 2

You need to use it in combination with a Character set.
NSCharacterSet *charSet = [NSCharacterSet decimalDigitCharacterSet];
NSScanner *scanner = [NSScanner scannerWithString:url];
[scanner scanUpToCharactersFromSet:charSet intoString:nil];
int urlId;
[scanner scanInt:&urlId];
Of course, this is only if you know that numbers won't appear in the URL path before the ID. If they might, you'd need to get a little more robust than this, but you could use this snippet as a starting point.