How do you change the elements within an NSArray?

Question

I am a bit confused as to how arrays are handled in Objective-C. If I have an array such as

NSarray *myArray = [[NSArray alloc]
                                  initWithObjects:@"N", @"N", @"N", @"N", @"N",
                                  nil];

how do I change the first occurrence to "Y"?

Answer 1

You need an NSMutableArray ..

NSMutableArray *myArray = [[NSMutableArray alloc]
                                  initWithObjects:@"N", @"N", @"N", @"N", @"N",
                                  nil];

and then

[myArray replaceObjectAtIndex:0 withObject:@"Y"];

Answer 2

You can't, because NSArray is immutable. But if you use NSMutableArray instead, then you can. See replaceObjectAtIndex:withObject::

[myArray replaceObjectAtIndex:0 withObject:@"Y"]