Best way to sort an NSArray of NSDictionary objects?

Question

I'm struggling with trying to sort an array of dictionaries.

My dictionaries have a couple of values of interest, price, popularity etc.

Any suggestions?

Solution 1

Use NSSortDescriptor like this..

NSSortDescriptor * descriptor = [[NSSortDescriptor alloc] initWithKey:@"interest" ascending:YES];
stories = [stories sortedArrayUsingDescriptors:@[descriptor]];
recent = [stories copy];

stories is the array you want to sort. recent is another mutable array which has sorted dictionary values. Change the @"interest" with the key value on which you have to sort.

All the best

Solution 2

[array sortUsingDescriptors:[NSArray arrayWithObjects:[NSSortDescriptor sortDescriptorWithKey:@"YOUR-KEY" ascending:YES], nil]];

I don't really want to break it into multiple lines. It's already simple enough for me.

Solution 3

You can just traverse from the parent to the required child property. For e.g.

NSSortDescriptor *descriptor = [[NSSortDescriptor alloc] initWithKey:@"parent.child.child"  ascending:YES];

Solution 4

Update , sortUsingDescriptors is now sortedArrayUsingDescriptors

So, its like:

items  = [items sortedArrayUsingDescriptors:[NSArray arrayWithObjects:descriptor,nil]];

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Comments

[Tom Andersen]

This is good, but it does leak. 1) the sort descriptor should be released or autoreleased, and 2) The copy call is not needed the line can be deleted.

[Tom Andersen]

NSSortDescriptor *descriptor = [[[NSSortDescriptor alloc] initWithKey:@"interest" ascending:YES] autorelease]; [stories sortUsingDescriptors:[NSArray arrayWithObjects:descriptor,nil]];

[maxcanna]

You can use NSSortDescriptor *descriptor = [NSSortDescriptor sortDescriptorWithKey:@"interest" ascending:YES];

[J3RM]

recent = [[stories sortedArrayUsingDescriptors:[NSArray arrayWithObjects:descriptor,nil]] copy];

[johndpope]

NSSortDescriptor *descriptor = [NSSortDescriptor sortDescriptorWithKey:@"name" ascending:YES]; [resultArray1 sortUsingDescriptors:[NSArray arrayWithObjects:descriptor,nil]];

[Rob]

You need to store the output during the sort call: NSArray* recent = [stories sortedArrayUsingDescriptors:[NSArray arrayWithObjects:descriptor,nil]];

[Dalzhim]

You seem to be confusing - [NSArray sortedArrayUsingDescriptors] and - [NSMutableArray sortUsingDescriptors]. The latest still exists and hasn't been replaced.

[Rambatino]

You little star. this helped me sort a sub sub dictionary. Thanks a lot!

[Rambatino]

It doesn't answer the question!

[Mrugesh Tank]

Can I use "@allkey" type value in init of sortDescriptor ?

[Victor Kwok]

if stories is a mutable array, you can use [stories sortUsingDescriptors:@[descriptor]]; instead