Sort array with dictionaries by date - ios

Question

I have an NSArray with NSDictionary inside. It looks like:
etc.
I need to sort it by date inside NSDictionary. I need something like this:
How can I do this? Here is my method which gives me first unsorted array:
- (void)iterateOverDocumentsDirectory
{
arrayWithFiles = [NSMutableArray new];
NSFileManager *fileManager = [[NSFileManager alloc] init];
NSError *error;
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *documentsDirPath = [paths objectAtIndex:0];
NSString *finalPathToFolder = [NSString stringWithFormat:#"%#/", documentsDirPath];
albumNames = [[fileManager contentsOfDirectoryAtPath:finalPathToFolder error:&error] mutableCopy];
if (albumNames == nil) {
// error...
}
for (NSString *album in albumNames)
{
NSMutableDictionary *tempDict = [[NSMutableDictionary alloc] init];
[tempDict setValue:album forKey:#"name"];
NSString *finalPathToFiles = [NSString stringWithFormat:#"%#/%#", documentsDirPath, album];
NSArray *tempArray = [fileManager contentsOfDirectoryAtPath:finalPathToFiles error:&error];
NSMutableArray *arrayWithEachFiles = [NSMutableArray new];
for (NSString *tempString in tempArray)
{
NSMutableDictionary *eachFileDict = [[NSMutableDictionary alloc] init];
NSString *pathToFile = [NSString stringWithFormat:#"%#/%#/%#", documentsDirPath, album, tempString];
[eachFileDict setValue:pathToFile forKey:#"path"];
NSDictionary *filePathsArray1 = [[NSFileManager defaultManager] attributesOfItemAtPath:pathToFile error:nil];
NSDate *modifiedDate = [filePathsArray1 objectForKey:NSFileCreationDate];
[eachFileDict setValue:modifiedDate forKey:#"date"];
[arrayWithEachFiles addObject:eachFileDict];
}
NSSortDescriptor *ageDescriptor = [[NSSortDescriptor alloc] initWithKey:#"date" ascending:YES];
NSArray *sortDescriptors = #[ageDescriptor];
NSArray *sortedArrayWithFiles = [[arrayWithEachFiles sortedArrayUsingDescriptors:sortDescriptors] mutableCopy];
[tempDict setValue:sortedArrayWithFiles forKey:#"files"];
[arrayWithFiles addObject:tempDict];
}
}

Answer 1

Use following code for sorting the array of dictionaries:
NSArray * sortedArray = [myArray sortedArrayUsingComparator:^(id obj1, id obj2) {
NSNumber *rating1 = [(NSDictionary *)obj1 objectForKey:#"date"];
NSNumber *rating2 = [(NSDictionary *)obj2 objectForKey:#"date"];
return [rating1 compare:rating2];
}];

Answer 2

You can sort it easily by using sortArrayUsingComparator:
[array sortedArrayUsingComparator:^NSComparisonResult(id obj1, id obj2) {
return //pseudo-code: {obj1->dict->date isLaterThan obj2->dict->date};
}];

Answer 3

I sort it. Not sure that my code is clear and well optimized. But here is a solution:
NSMutableArray *masterArray = [NSMutableArray new];
NSMutableArray *sameDates = [NSMutableArray new];
BOOL started = NO;
NSString *prevDate;
for (NSDictionary *dict in sortedArrayWithFiles)
{
NSString *tempString = [dict objectForKey:#"date"];
if (started)
{
if ([tempString isEqualToString:prevDate])
{
[sameDates addObject:dict];
}
else
{
NSMutableDictionary *tempDict = [[NSMutableDictionary alloc] init];
[tempDict setValue:tempString forKey:tempString];
[tempDict setValue:sameDates forKey:#"files"];
[masterArray addObject:tempDict];
prevDate = tempString;
[sameDates removeAllObjects];
[sameDates addObject:tempString];
}
}
else
{
// first element
started = YES;
prevDate = tempString;
[sameDates addObject:dict];
}
}
// last value
NSMutableDictionary *tempDict = [[NSMutableDictionary alloc] init];
[tempDict setValue:prevDate forKey:prevDate];
[tempDict setValue:sameDates forKey:#"files"];
[masterArray addObject:tempDict];
In master array we store array with dictionaries separated by date.