iphone - Comparing Two Arrays

Question

I have two NSArrays, what I'm looking to do is to compare two arrays which contain strings, find the similarities and create the first array again but so they have no similarities.

Just for an example something like.

Two Arrays:

NSArray *arrayOne = [NSArray arrayWithObjects:@"TD1", @"TD2", @"TD3", nil];
NSArray *arrayTwo = [NSArray arrayWithObjects:@"Blah", @"String", @"TD2", nil];

Outcome:

NSArray *arrayOne = [NSArray arrayWithObjects:@"TD1", @"TD2", @"TD3", nil];

NSArray *arrayOneCopy = [NSArray arrayWithObjects:@"TD1", @"TD3", nil];
NSArray *arrayTwo = [NSArray arrayWithObjects:@"Blah", @"String", @"TD2", nil];

Answer 1

NSMutableArray *arrayOneCopy = [NSMutableArray arrayWithArray:arrayOne];
[arrayOneCopy removeObjectsInArray:arrayTwo];