Question

Why is the count of otherArray 0 even though self.array has N items and the for loop is executing N times?

for (MyObject *obj in self.array) 
{
    [self.otherArray addObject:obj];
    NSLog(@"Num items: %d", [self.otherArray count]);
} 

self.otherArray is an NSMutableArray*

LATER: Doh!, forgot to call alloc/init (I come from a language where the equivalent of addObejct will create the array if necessary).

Answer 1

In this case, the most common reason this would occur is if self.otherArray isn’t initialized. If you add a check to self.otherArray, I would suspect it is nil. If you added:

self.otherArray = [[NSMutableArray alloc] init];

right before the other code, I suspect it would work as intended.