iOS macOS拼接字符串

1.stringWithFormat

    NSString *str1 = @"666";
    NSString *str2 = @"888";
    NSString *strAll = [NSString stringWithFormat:@"%@%@",str1, str2];

     NSLog(@"输出结果：%@",strAll);

输出结果：666888

 2.initWithFormat

    NSString *str1 = @"555";
    NSString *str2 = @"777";
    NSString *strAll = [[NSString alloc]initWithFormat:@"%@%@",str1,str2];

     NSLog(@"输出结果：%@",strAll);

输出结果：555777

3.stringByAppendingString

    NSString *str1 = @"333";
    NSString *str2 = @"444";
    NSString *strAll = [str1 stringByAppendingString:str2];

      NSLog(@"输出结果：%@",strAll);

输出结果：333444

4.可变字符串NSMutableString

    NSString *str1 = @"555";
    NSString *str2 = @"777";
    NSMutableString *strAll = [NSMutableString string];
    [strAll appendString:str1];
    [strAll appendString:str2];

      NSLog(@"输出结果：%@",strAll);

输出结果：555777

5.stringByAppendingFormat

    NSString *str1 = @"888";
    NSString *str2 = @"999";
    NSString *strAll = [[NSString alloc]init];//或者这样初始化 NSString *strAll = [NSString string];    
    strAll = [strAll stringByAppendingFormat:@"%@%@",str1,str2];

    NSLog(@"输出结果：%@",strAll);

输出结果：888999