以周为单位对 NSDate 进行分组，并从最新到最旧排序

Question

我正在为 iPhone 开发一个应用程序，我坚持到这一点：

我从对象中获取此数据：

{
    date = "2014-08-04 11:21:26 +0000";
    idChallenger = "-1";
    index = "-1";
    time = "-1";
},
   {
    date = "2015-07-31 14:50:40 +0000";
    idChallenger = 43;
    index = "-1";
    time = "-1";
},
    {
    date = "2015-07-31 16:18:57 +0000";
    idChallenger = "-1";
    index = "-1";
    time = "-1";
},
    {
    date = "2015-07-31 16:19:29 +0000";
    idChallenger = "-1";
    index = "-1";
    time = "-1";
},
    {
    date = "2015-08-04 15:25:26 +0000";
    idChallenger = "-1";
    index = "-1";
    time = "-1";
}

现在我应该获取所有日期，按周分组并从最新到最旧排序...

此时我坚持如何按周对 NSDate 进行分组，当日期中的年份更多时问题就开始了，因为例如结构中的第一个元素被最后一个元素分组。

我该怎么办？谢谢

编辑:

这是我用来按周分组的代码：

NSMutableArray *weekArray = [NSMutableArray array];
for (int i = 0; i<52; i++) {

    [weekArray addObject:[NSMutableArray array]];
}


for (int i = 0; i<_array.count; i++) {

    NSDictionary *dict = [_array objectAtIndex:i];

    NSDate *date = [dict objectForKey:@"date"];

    NSCalendar *calendar = [NSCalendar currentCalendar];

    NSDateComponents *dateComponents = [calendar components:NSCalendarUnitYear | NSCalendarUnitWeekOfYear fromDate:date];

    NSMutableArray *innerArray = weekArray[[dateComponents weekOfYear] -1];
    [innerArray addObject:dict];
}

for (int i = 0; i<weekArray.count; i++) {

    if ([[weekArray objectAtIndex:i] count] > 0) {

        NSNumber *iNum = [NSNumber numberWithInt:i+1];

        [_mutableDictionary setObject:[weekArray objectAtIndex:i] forKey:iNum];
    }
}

_mutableDictionary 是：

31 =     (
            {
        date = "2015-07-31 16:19:29 +0000";
        idChallenger = "-1";
        index = "-1";
        time = "-1";
    },
            {
        date = "2015-07-31 16:19:23 +0000";
        idChallenger = "-1";
        index = "-1";
        time = "-1";
    },
            {
        date = "2015-07-31 16:18:57 +0000";
        idChallenger = "-1";
        index = "-1";
        time = "-1";
    },
            {
        date = "2015-07-31 14:50:40 +0000";
        idChallenger = 43;
        index = "-1";
        time = "-1";
    }
);
32 =     (
            {
        date = "2015-08-04 15:25:26 +0000";
        idChallenger = "-1";
        index = "-1";
        time = "-1";
    },
            {
        date = "2014-08-04 11:22:40 +0000";
        idChallenger = 43;
        index = "-1";
        time = "-1";
    }
);

31 和 32 是一年中的周数

我认为这不符合我的目标...

以正确的方式对这个 NSDate 进行分组后，我必须有一个结构允许我每周在 UITableView 中创建 n 个部分

Answer 1

您需要根据年份和年份中的星期进行分组。您还需要避免对 52 个空数组进行硬编码。相反，使用数组字典，其中键代表年和周，值是数组。

尝试这样的事情：

NSMutableDictionary *weeksDictionary = [NSMutableDictionary dictionary];

NSCalendar *calendar = [NSCalendar currentCalendar];
for (NSDictionary *dict in _array) {
    NSDate *date = [dict objectForKey:@"date"];
    NSDateComponents *dateComponents = [calendar components:NSCalendarUnitYear | NSCalendarUnitWeekOfYear fromDate:date];
    NSInteger year = dateComponents.year;
    NSInteger week = dateComponents.weekOfYear;
    NSInteger index = year * 100 + week;
    NSNumber *key = @(index);
    NSMutableArray *weekArray = weeksDictionary[key];
    if (!weekArray) {
        weekArray = [NSMutableArray array];
        weeksDictionary[key] = weekArray;
    }
    [weekArray addObject:dict];
}

这为每个 year/week 具有日期的数组提供了一个数组。

要将其与 table 视图一起使用，请对字典的键进行排序以获得按顺序排列的 year/week 个值的数组。然后你可以拆分每个键得到年和周：

NSNumber *key = sortedKeysArray[indexPath.section];
NSInteger value = key.integerValue;
NSInteger year = value / 100;
NSInteger week = value % 100;

以周为单位对 NSDate 进行分组，并从最新到最旧排序

Group NSDate in weeks and order from newest to oldest

objective-c

nsdate

nsdatecomponents

ios