how to add nil to nsmutablearray?

Question

NSArray *array = [[NSArray alloc] initWithObjects:@"ΕΛΤΑ",
                      @"ΕΛΤΑ COURIER", @"ACS", @"ACS ΕΞΩΤΕΡΙΚΟ", 
                      @"DHL", @"INTERATTICA", @"SPEEDEX", 
                      @"UPS", @"ΓΕΝΙΚΗ ΤΑΧΥΔΡΟΜΙΚΗ", @"ΜΕΤΑΦΟΡΙΚΕΣ ΕΞΩΤΕΡΙΚΟΥ", nil];

This is working because it has nil at the end.

But I add objects like this: addObject:name etc... So at the end I have to add nil I do this addObhect:nil but when I run the app it still crashes at cellForRowAtIndexPath:

how can I do this work?

Ok, I dont have to add nil

What is the reason that my app crashes then?

user_133764 · Answer

If you must add a nil object to a collection, use the NSNull class:

The NSNull class defines a singleton object used to represent null values in collection objects (which don’t allow nil values).

Assuming "array" is of type NSMutableArray:

....
[array addObject:[NSNumber numberWithInt:2];
[array addObject:@"string"];
[array addObject:[NSNull null]];

user_49658 · Answer

You don't need to call [addObject:nil]

The nil in initWithObjects: is only there to tell the method where the list ends, because of how C varargs work. When you add objects one-by-one with addObject: you don't need to add a nil.

user_237696 · Answer

You can't add nil when you're calling addObject.

David_Grant_26829 · Answer

If you really want a Null-ish item in your collection, NSNull is there for that.

user_170176 · Answer

nil is used to terminate the array

mouviciel_45249 · Answer

nil is not an object that you can add to an array: An array cannot contain nil. This is why addObject:nil crashes.

user_190807 · Answer

You can't add an object to an NSArray because that class is immutable. You have to use NSMutableArray if you want to change the array after it is created.

how to add nil to nsmutablearray?

9 Answers