ios获取html字符串中的title

NSError *error;
  NSString *htmlStr = [NSString stringWithContentsOfURL:[NSURL URLWithString:@"https://www.baidu.com"] encoding:NSUTF8StringEncoding error:&error];
    if (!error && htmlStr.length) {
        NSRange range = [htmlStr rangeOfString:@"(?<=title>).*(?=</title)"  options:NSRegularExpressionSearch range:NSMakeRange(0, htmlStr.length - 1) locale:nil];
        NSString *title = [htmlStr substringWithRange:range];
    }