As the Apple documentation about deep copies explicitly states:
If you only need a one-level-deep copy:
NSMutableArray *newArray = [[NSMutableArray alloc] initWithArray:oldArray copyItems:YES];
The above code creates a new array whose members are shallow copies of the members of the old array.
Note that if you need to deeply copy an entire nested data structure — what the linked Apple docs call a true deep copy — then this approach will not suffice. Please see the other answers here for that.