Question

So I have a strong collection variable x (of type NSMutableArray e.g.), when doing dealloc, if I only do x = nil, would it be the same effect as the following?

[x removeAllObjects]; 
[x release]; // not needed in ARC
x = nil; 

Answer 1

Strictly speaking, the two are not identical. Setting a strong variable to nil will indeed release the object. However, an array will only removeAllObjects if it is getting destroyed. If another variable holds a strong reference to the array, it will stay alive and not remove the items it contains.