Question

I have a NSString in an NSArray and I wanted to order this string/fields based on how important it is. So say the string is B, H, A, Q, Z, L, M, O.

I wanted it to be always sorted as A, Q, Z, B, H, O, L, M. This is a predefined set of rule. How do I do this? Can this be done using NSSortDescriptor?

Answer 1

NSArray has several sort functions. Three you might consider are:

- (NSArray *)sortedArrayUsingComparator:(NSComparator)cmptr

- (NSArray *)sortedArrayUsingSelector:(SEL)comparator

- (NSArray *)sortedArrayUsingFunction:(NSInteger (*)(id, id, void *))comparator context:(void *)context

I think you might find the second, selector-based comparator the easiest to use to get started. See the docs here:

https://developer.apple.com/library/mac/documentation/Cocoa/Reference/Foundation/Classes/NSArray_Class/NSArray.html#//apple_ref/occ/instm/NSArray/sortedArrayUsingSelector:

EDIT:

I think using NSSortDescriptor may be overkill, but here is a good post describing it:

How to sort NSMutableArray using sortedArrayUsingDescriptors?