日期字符串或对象的排序 NSArray

Once you have an NSDate, you can create an NSSortDescriptor with initWithKey:ascending: and then use sortedArrayUsingDescriptors: to do the sorting.

You can use sortedArrayUsingFunction:context:. Here is a sample:

NSComparisonResult dateSort(NSString *s1, NSString *s2, void *context) {
NSDate *d1 = [NSDate dateWithString:s1];
NSDate *d2 = [NSDate dateWithString:s2];
return [d1 compare:d2];
}


NSArray *sorted = [unsorted sortedArrayUsingFunction:dateSort context:nil];

When using a NSMutableArray, you can use sortArrayUsingFunction:context: instead.

Store the dates as NSDate objects in an NS(Mutable)Array, then use -[NSArray sortedArrayUsingSelector: or -[NSMutableArray sortUsingSelector:] and pass @selector(compare:) as the parameter. The -[NSArray sortedArrayUsingSelector:0 method will order dates in ascending order for you. This is simpler than creating an NSSortDescriptor, and much simpler than writing your own comparison function. (NSDate objects know how to compare themselves to each other at least as efficiently as we could hope to accomplish with custom code.)

If I have an NSMutableArray of objects with a field "beginDate" of type NSDate I am using an NSSortDescriptor as below:

NSSortDescriptor *sortDescriptor = [[NSSortDescriptor alloc] initWithKey:@"beginDate" ascending:TRUE];
[myMutableArray sortUsingDescriptors:[NSArray arrayWithObject:sortDescriptor]];
[sortDescriptor release];

You can use blocks to sort in place:

sortedDatesArray = [[unsortedDatesArray sortedArrayUsingComparator: ^(id a, id b) {
NSDate *d1 = [NSDate dateWithString: s1];
NSDate *d2 = [NSDate dateWithString: s2];
return [d1 compare: d2];
}];

I suggest you convert all your strings to dates before sorting not to do the conversion more times than there are date items. Any sorting algorithm will give you more string to date conversions than the number of items in the array (sometimes substantially more)

a bit more on blocks sorting: http://sokol8.blogspot.com/2011/04/sorting-nsarray-with-blocks.html

You may also use something like the following:

//Sort the array of items by  date
[self.items sortUsingComparator:^NSComparisonResult(id obj1, id obj2){
return [obj2.date compare:obj1.date];
}];

But this does assume that the date is stored as a NSDate rather a NString, which should be no problem to make/do. Preferably, I recommend also storing the data in it's raw format. Makes it easier to manipulate in situations like this.

Change this

NSSortDescriptor *sortDescriptor = [[NSSortDescriptor alloc] initWithKey:@"beginDate" ascending:TRUE];
[myMutableArray sortUsingDescriptors:[NSArray arrayWithObject:sortDescriptor]];
[sortDescriptor release];

To

NSSortDescriptor *sortDescriptor = [[NSSortDescriptor alloc] initWithKey:@"Date" ascending:TRUE];
[myMutableArray sortUsingDescriptors:[NSArray arrayWithObject:sortDescriptor]];
[sortDescriptor release];

Just change the KEY: it must be Date always

What it worked in my case was the following:

    NSArray *aUnsorted = [dataToDb allKeys];
NSArray *arrKeys = [aUnsorted sortedArrayUsingComparator:^NSComparisonResult(id obj1, id obj2) {
NSDateFormatter *df = [[NSDateFormatter alloc] init];
[df setDateFormat:@"dd-MM-yyyy"];
NSDate *d1 = [df dateFromString:(NSString*) obj1];
NSDate *d2 = [df dateFromString:(NSString*) obj2];
return [d1 compare: d2];
}];

I had a dictionary, where all keys where dates in format dd-MM-yyyy. And allKeys returns the dictionary keys unsorted, and I wanted to present the data in chronological order.

Swift 3.0

myMutableArray = myMutableArray.sorted(by: { $0.date.compare($1.date) == ComparisonResult.orderedAscending })