ios 字符串拼装 NSString连接

1、

ac.rmname =  [@"Str"  stringByAppendingFormat:@"%@%@%@",@"str1",@"-",@"str2"];

2、

  NSMutableString *keystr = [[NSMutableStringalloc]initWithCapacity:10];

        

        [keystr appendFormat:@"%d",8];

        [keystr appendFormat:@"-"];

        [keystr appendFormat:@"%d",9];