iphone sdk排序问题

Question

遇到一些问题，我对其进行了排序，但看起来像这样，

"10/16/2011 12:00:00 AM",
    "10/16/2011 12:00:00 AM",
    "11/16/2011 12:00:00 AM",
    "11/16/2011 12:00:00 AM",
    "9/15/2011 12:00:00 AM",
    "9/15/2011 12:00:00 AM",
    "9/15/2011 12:00:00 AM"

格式是“MM/dd/yyyy”，我想根据日、月、年、时间对其进行排序。我怎样才能实现它？

这是代码

NSSortDescriptor* nameSorter = [[NSSortDescriptor alloc] initWithKey:nil ascending:YES];
NSMutableArray *temp = [dateStart mutableCopy];
[temp sortUsingDescriptors:[NSArray arrayWithObject:nameSorter]];
dateStart = temp;
NSLog(@"Sorted: %@",dateStart);

Answer 1

您可以使用 NSDateFormatter 将字符串转换为 NSDate 并使用 Comparator 进行比较，

NSArray *datesArray = @[@"10/16/2011 12:00:00 AM",
                   @"10/16/2011 12:00:00 AM",
                   @"11/16/2011 12:00:00 AM",
                   @"11/16/2011 12:00:00 AM",
                   @"9/15/2011 12:00:00 AM",
                   @"9/15/2011 12:00:00 AM",
                   @"9/15/2011 12:00:00 AM"];

NSLog(@"dates:%@", datesArray);

NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
[dateFormatter setDateFormat:@"MM/dd/yyyy h:mm:ss a"];

NSArray *sortedDatesArray = [datesArray sortedArrayUsingComparator:^(id obj1, id obj2){

    NSDate *date1 = [dateFormatter dateFromString:obj1];
    NSDate *date2 = [dateFormatter dateFromString:obj2];

    return [date1 compare:date2];

}];

NSLog(@"%@",sortedDatesArray);

输出：

"9/15/2011 12:00:00 AM",
"9/15/2011 12:00:00 AM",
"9/15/2011 12:00:00 AM",
"10/16/2011 12:00:00 AM",
"10/16/2011 12:00:00 AM",
"11/16/2011 12:00:00 AM",
"11/16/2011 12:00:00 AM"