ios 排除字符串中的非数字 取出数字

NSString *urlString = @"请联系购票管家电话167-6767$#6763--";
NSString *stewardNumbers = [[urlString componentsSeparatedByCharactersInSet:[[NSCharacterSet characterSetWithCharactersInString:@"0123456789"] invertedSet]] componentsJoinedByString:@""];
NSLog(@"请联系管家---%@--",stewardNumbers);
最后输出"请联系管家---16767676763--;