How to combine two key values in the dictionary of array in Objective C - objective-c

Question

I am having the multiple objects of the dictionary in the array. Now, in particular dictionary i have two keys "category" and "createdDate" from the other key.
Situation : -
I Need an array which having objects in a such a way that, the category which having the same date can be clubbed together and form an object . and Those category having different date is the other object it self.
I am having situation in my mind where i have to put various comparison conditions between the keys , the basic approach of doing it . --- Not Required
Need your valuable suggestion for Different Approach, Which is required, also is not complex. Thanks in advance.

Answer 1

here you go, an example
NSDateFormatter * df = [NSDateFormatter new];
for (id object in self.mainArray) {
[df setDateFormat:#"MM/dd/yyyy"];
NSString *dateString = [df stringFromDate:[object objectForKey:#"createdDate"]];
NSMutableArray *sectionArray = self.totalsSectionDictionary[dateString];
if (!sectionArray) {
sectionArray = [NSMutableArray array];
self.totalsSectionDictionary[dateString] = sectionArray;
}
NSString * tempString = [object valueForKey:#"category"]
[sectionArray addObject:#{#"value" : tempString}];
}
this results in a dictionary of objects combined by date as a string value and inside each one of those date keys resides an array of values for that date. From there, you need to tease out those values and sort them like so:
NSArray * tempUnsortedArray = [self.totalsSectionDictionary allKeys];
NSArray *arrKeys = [tempUnsortedArray sortedArrayUsingComparator:^NSComparisonResult(id obj1, id obj2) {
NSDateFormatter *df = [[NSDateFormatter alloc] init];
[df setDateFormat:#"MM/dd/yyyy"];
NSDate *d1 = [df dateFromString:(NSString*) obj1];
NSDate *d2 = [df dateFromString:(NSString*) obj2];
return [d2 compare: d1];
}];
NSMutableArray * tempArray1 = [NSMutableArray array];
for (NSInteger i = 0; i < arrKeys.count; i++) {
NSMutableArray *sectionArray = self.totalsSectionDictionary[arrKeys[i]];
}
there you go, the last for loop will allow you to iterate through each section array stored in the original dictionary by date so you can put them into a collection or table view
good luck