Question

I’m trying to sort a multidimensional array in objective-c i know that i can sort a single dimensional array using the line of code below:

NSArray *sortedArray = [someArray sortedArrayUsingSelector:@selector(caseInsensitiveCompare:)];

I can’t seem to figure out how to sort a 2D array like the one below:

 ( ("SOME_URL", "SOME_STORY_TITLE", "SOME_CATEGORY"),
    ("SOME_URL", "SOME_STORY_TITLE", "SOME_CATEGORY"),
    ("SOME_URL", "SOME_STORY_TITLE", "SOME_CATEGORY") );

If someone could provide me code that would sort the array by SOME_CATEGORY it would be of great help to me.

Thanks,

Zen_Silence

Answer 1

You need to use -sortedArrayUsingFunction:context: or sortedArrayUsingFunction:context:hint:.

static NSInteger order (id a, id b, void* context) {
    NSString* catA = [a lastObject];
    NSString* catB = [b lastObject];
    return [catA caseInsensitiveCompare:catB];
}
...
NSArray* sortedArray = [someArray sortedArrayUsingFunction:order context:NULL];

Alternatively, create a custom class for your inner “array” (which is more like a record), and implement a -compareByCategory: method on it.