Question

so basically like the title says is there a way to use NSSortDescriptor to sort the results of a NSFetchRequest based on a specific attributes (that is a string) length with respect to number of characters?

For example
Order of results would be:

A
AA
AAA
AAAA

and so on

Thanks a lot everyone! I can’t figure this one out

This is the sort descriptor i was trying:

NSSortDescriptor* sort = [NSSortDescriptor sortDescriptorWithKey:@"food_name" ascending:YES comparator:^(id obj1, id obj2) {
    NSInteger len1 = [obj1 length];
    NSInteger len2 = [obj2 length];
    if (len1 < len2) return NSOrderedAscending;
    if (len1 > len2) return NSOrderedDescending;
    return NSOrderedSame;
}];

I put a breakpoint in it and it doesn’t seem to be getting called.

Answer 1

You can write a sort descriptor with a custom comparator. Blocks make it really easy!

[NSSortDescriptor sortDescriptorWithKey:@"stringName"
 ascending:YES
 comparator:^(id obj1, id obj2) {
    NSInteger len1 = [obj1 length];
    NSInteger len2 = [obj2 length];
    if (len1 < len2) return NSOrderedAscending;
    if (len1 > len2) return NSOrderedDescending;
    return NSOrderedSame;
 }];