An easy way to match NSString with a Regex
NSString *string = @"/sc/trovesband/youth_in_decay#https://api.soundcloud.com/tracks/162801570/stream";
NSString *regex = @"(tracks)\\/([\\d]+)";Get the first or the only group
NSString *result = [string firstMatchedGroupWithRegex:regex];
//result = tracks;Get a specific match
NSString *result = [string matchWithRegex:regex atIndex:2];
//result = 162801570;Get all match
NSArray *results = [string matchWithRegex:regex];
//results = ["tracks/162801570", "tracks", "162801570"]