Question

Noob在这里。我最近开始使用目标C，目前我坚持使用字典概念。我想创建一个json对象，如下所示：

{"UserData": {
              "Name": Mike Smith,
              "Age": 32,
              "category": [1,2,3],
              "Weekly Data": [
                               {"Monday" : [1.0,2.0,3.0]},
                               {"Tuesday": [1.0,2.0,3.0]}
                             ]
              }
}

我编写了以下代码，但未提供所需的结果。我想知道是否有人可以帮助我。

    -(NSString*)populateUserPreferences
{
    NSMutableDictionary *dict = [[NSMutableDictionary alloc] init];
    NSMutableArray *categorydata = [[NSMutableArray alloc] init];
    NSMutableArray *weeklydata = [[NSMutableArray alloc] init];

    for (int i=0;i<4; i++) 
    {
        [categorydata addObject:[NSNumber numberWithInt:i]];
    }


        NSMutableArray *mondaydata = [[NSMutableArray alloc] init];
        for (int j=0; j<3; j++)
        {
            [mondaydata addObject:[NSNumber numberWithInt:j]];
        }

        NSMutableArray *tuesdaydata = [[NSMutableArray alloc] init];
        for (int j=0; j<3; j++)
        {
            [tuesdaydata addObject:[NSNumber numberWithInt:j]];
        }


      NSDictionary *monday  = [NSDictionary dictionaryWithObject:mondaydata];
      NSDictionary *tuesday = [NSDictionary dictionaryWithObject:tuesdaydata];

        [weeklydata addObject: monday  ];
        [weeklydata addObject: tuesday ];

    }

    [dict setObject:[NSString stringWithFormat:"Mike Smith"] forKey:@"Name"];
    [dict setObject:[NSNumber numberWithInteger:32.0] forKey:@"Age"];

    [dict setObject:categorydata forKey:@"category"];
    [dict setObject:weeklydata forKey:@"Weekly Data"];

    NSString * userdata = [dict JSONRepresentation];
    NSLog(request);

    NSDictionary *userdataJson = [NSDictionary dictionaryWithObject:dict forKey:@"userData"];

    return [userdataJson JSONRepresentation];
}

提前感谢您对此进行调查。

Apoorva

Answer 1

错误在于创建星期一和星期二字典。

const http = require('http');
const server = http.createServer((req,res) => {
    const data = {
        'data': 'Hello World',
        'hostname': require('os').hostname()
    };
    res.writeHead(200, {'Content-Type': 'application/json'})
    res.end(JSON.stringify(data));
});

server.listen(process.env.PORT, (err) => {
    if (err)
     return console.log(err);
    console.log('API is running on ' + process.env.PORT);
})

此代码错误，因为您没有正确分配字典（字典的键在哪里？）。相反，你应该这样做：

// mondaydata & tuesday is just array.
NSDictionary *monday  = [NSDictionary dictionaryWithObject:mondaydata];
NSDictionary *tuesday = [NSDictionary dictionaryWithObject:tuesdaydata];

然后你可以将mondayDict和tuesdayDict添加到你的数组weeklydata。

PS。只是一个注释，有意义地命名您的变量。例如，mondaydata不够描述。你应该使用mondayArr作为例子。要轻松识别它是一个数组。只是一个正常的编码实践来分享。

Answer 2

NSDictionary * dict = @{@"UserData": @{
                                @"Name": @"Mike Smith",
                                @"Age": @32,
                                @"category": @[@1,@2,@3],
                                @"Weekly Data": @[
                                        @{@"Monday" : @[@1.0,@2.0,@3.0]},
                                        @{@"Tuesday": @[@1.0,@2.0,@3.0]}
                                        ]
                                }
                        };
NSError * error = nil;
NSData * data = [NSJSONSerialization dataWithJSONObject:dict options:NSJSONWritingPrettyPrinted error:&error];
if (error) {
    NSLog(@"%@", [error localizedDescription]);
} else {
    // Do what you want
}

创建一个包含字典数组的字典

2 个答案: