Question

If I have a mutable array “codes” in an NSMutableDictionary “categorize”

  NSMutableArray *myMutableArray=(NSMutableArray*)[categorize objectForKey:@"codes"];

and I add objects from another non-mutable array “templateCodes” in an NSDictionary “templateCategorize”

  [codes addObjectsFromArray:(NSArray*)[templateCategorize objectForKey:@"templateCodes"]];

does the codes array become “non-mutable” because I copied elements from a non-mutable array (templateCodes)?

This code works the first time objects are copied, but the second time this code is executed I get an error that the “addObjectsFromArray” selector is not valid indicating the array is non-mutable.

Answer 1

I don’t think it should make your mutable array immutable — a mutable array can contain immutable objects, so adding objects from another array shouldn’t make it immutable. This code works fine:

NSArray *theData = [NSArray arrayWithObjects:@"One",@"Two",@"Three",nil];
NSMutableArray *mut = [NSMutableArray arrayWithObjects:@"Four",@"Five",@"Six",nil];
[mut addObjectsFromArray:theData];
NSLog(@"%@",mut);
NSLog(@"%@",[mut class]);
[mut addObject:@"seven"];
NSLog(@"%@",mut);

Something else must be going on in your code that I’m not seeing.