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ios - 如何对数组中的日期进行分组？

问题描述

我的日期格式是这样的“2019-12-03T05:58:11.317Z”。我想对相同的日期元素进行分组。我可以根据日期创建 UITableView 部分。这是数组，我有三个不同的日期，所以我想创建 3 个部分。这里的问题是newArrayList没有保存所有元素。

        NSMutableArray * arrayList;
        NSMutableArray *newArrayList;
        //This is my date array
        arrayList = [[NSMutableArray alloc] initWithObjects:@“2019-12-03T05:58:11.317Z”, @“2019-12-03T05:58:10.317Z”, @“2019-12-03T05:58:01.317Z”, @“2019-12-03T05:55:12.448Z”, @“2019-12-03T05:48:11.317Z”, @“2019-12-03T05:28:11.317Z”, @“2019-12-03T05:11:24.004Z”, @“2019-12-03T05:28:11.317Z”, @“2019-12-03T05:55:12.965Z”, @“2019-12-02T15:09:35.408Z”, @“2019-12-02T15:09:38.187Z”, @“2019-12-02T15:43:02.118Z”, @“2019-12-02T15:44:09.344Z”, @“2019-12-02T17:07:55.038Z”, @“2019-12-02T16:42:16.649Z”, @“2019-12-01T16:42:16.649Z”, nil];

        newArrayList = [[NSMutableArray alloc]init];//Here I want to same date elements 

            NSDate *fromDate;
            NSMutableArray *tempArray = [[NSMutableArray alloc] init];
            for (int i=0; i<arrayList.count; i++) {
                NSDate *dt1 = fromDate;
                NSDate *dt2 = [self getLocalDateTimeFromUTC2:[arrayList objectAtIndex:i]];
                if (i != 0) {
                    if ([self isSameDay:dt1 otherDay:dt2] == YES) {
                        [tempArray addObject:t];
                    } else {
                        [newArrayList addObject:tempArray];
                    //  [tempArray removeAllObjects];
                    }
                }
                fromDate = dt2;
            }

//To get required date formate
-(NSDate *)getLocalDateTimeFromUTC2:(NSString *)strDate
{

// create dateFormatter with UTC time format
NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
[dateFormatter setDateFormat:@"yyyy-MM-dd'T'HH:mm:ss.SSSZZZZ"]; //@"yyyy-MM-dd'T'HH:mm:ss.SSSZZZZ"
[dateFormatter setTimeZone:[NSTimeZone timeZoneWithAbbreviation:@"UTC"]];
//    NSLog(@"%@", t.dateAndTime); //2019-12-02T15:09:38.187Z
NSDate *date = [dateFormatter dateFromString:strDate]; // create date from string

// change to a readable time format and change to local time zone
[dateFormatter setDateFormat:@"dd-MM-yyyy"];
[dateFormatter setTimeZone:[NSTimeZone localTimeZone]];
NSString *timestamp = [dateFormatter stringFromDate:date];

NSDateFormatter *dateFormat = [[NSDateFormatter alloc] init];
[dateFormat setDateFormat:@"dd-MM-yyyy"];
[dateFormat setTimeZone:[NSTimeZone localTimeZone]];
NSDate *date2 = [dateFormat dateFromString:timestamp];
//    NSLog(@"%@", date2);

return date2;
}

//To compare two dates
- (BOOL)isSameDay:(NSDate*)date1 otherDay:(NSDate*)date2 {

NSCalendar* calendar = [NSCalendar currentCalendar];
unsigned unitFlags = NSCalendarUnitYear | NSCalendarUnitMonth |  NSCalendarUnitDay;
NSDateComponents* comp1 = [calendar components:unitFlags fromDate:date1];
NSDateComponents* comp2 = [calendar components:unitFlags fromDate:date2];
return [comp1 day]   == [comp2 day] && [comp1 month] == [comp2 month] && [comp1 year]  == [comp2 year];
}

标签： iosobjective-cxcodecocoa-touchnsarray

解决方案

尝试这个：

NSMutableDictionary *dictByDate = [NSMutableDictionary new];
NSMutableArray *newArr = [NSMutableArray new] ;

for(NSString *strDate in arrayList)
{

    // convert date to proper formate (if needed)

    NSDateFormatter *format = [[NSDateFormatter alloc] init];
    [format setDateFormat:@"yyyy-MM-dd'T'HH:mm:ss.SSSZZZZ"];
    NSDate *dateNew = [format dateFromString:strDate];
    [format setDateFormat:@"MMMM-dd-yyyy"];
    NSString *finalDateString = [format stringFromDate:dateNew];

    NSLog(@"%@",finalDateString) ;

    NSMutableArray *arrWithSameDate = dictByDate[finalDateString];
    if(! arrWithSameDate)
    {
        arrWithSameDate = [NSMutableArray new];
        dictByDate[finalDateString] = arrWithSameDate;
    }
    [arrWithSameDate addObject: strDate];

}

[newArr addObjectsFromArray:[dictByDate allValues]] ;

NSLog(@"group data: %@", newArr);

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