Inserting NSDictionary into sorted NSMutableArray - objective-c

Question

I want to insert an NSDictionary object into an array and have the array sorted by objectForKey.
I managed to do this by inserting, re-sorting and reloading the array, which works fine, but I figured there would be a better method, which there is, I just don't know how to use it.
Current code:
-(NSMutableArray*)sortArray:(NSMutableArray*)theArray {
return [[theArray sortedArrayUsingDescriptors:[NSArray arrayWithObject:[[NSSortDescriptor alloc] initWithKey:#"n"
ascending:YES]]] mutableCopy];
}
returns the re-sorted array. Fine. Works perfectly, but... is it the most efficient?
From another question I gather that this is the method to use to find the index to insert into:
NSUInteger newIndex = [array indexOfObject:newObject
inSortedRange:(NSRange){0, [array count]}
options:NSBinarySearchingInsertionIndex
usingComparator:comparator];
[array insertObject:newObject atIndex:newIndex];
The problem is I have no idea how to use the comparator method, and if that's even possible when I want to sort by objectForKey for each index.
Can anyone exemplify the above method when the key of the object (newObject in above example) to sort by is, let's say:
[newObject objectForKey:#"sortByThis"];

Answer 1

Use NSSortDescriptor
NSSortDescriptor *sortDescriptor = [[NSSortDescriptor alloc] initWithKey:#"sortByThisKey" ascending:YES];
NSArray *sortDescriptors = [NSArray arrayWithObject:sortDescriptor];
NSArray *sortedArray = [myArray sortedArrayUsingDescriptors:sortDescriptors];

Answer 2

here is the simple example for comparator
- (NSComparisonResult)compareResulst:(CustomObject *)otherObject {
if(self.name isEqualToString:key)
{
return NSOrderedAscending;
}
else
{
return NSOrderedDescending
}
}
NSArray *sArray;
sArray = [unsArray sortedArrayUsingSelector:#selector(compareResulst:)];
this will sort the array. it will iterate through object and based on your if else it will move object up and down ...

Answer 3

Here's an example of sorting
//For make a we're adding 5 random integers into array inform of NSDictionary
//here, we're taking "someKey" to store the integer (converted to string object) into dictionary
NSMutableArray *array = [NSMutableArray array];
for(int i = 1; i<=5; i++) {
[array addObject:[NSDictionary dictionaryWithObject:[#(arc4random()%10) stringValue] forKey:#"someKey"]];
}
//create a sort descriptor to sort the array
//give the key in dictionary for which you want to perform sort
NSSortDescriptor *sort = [NSSortDescriptor sortDescriptorWithKey:#"someKey" ascending:YES];
//we're doing self sort for mutable array, & that's it, you'll have a sorted array.
[array sortUsingDescriptors:#[sort]];
N.B.
1.Instead of "someKey" from above example you can set any key for which you want to perform sort.
2.There's some other methods for sorting, you can use the one base on your requirement.
3.see #[sort] in code. Its full version is, [NSArray arrayWithObject:sort];