Need clarification on addObjectsFromArray function

Question

I have the following code (both items and itemsCopy are NSMutableArray's):

//DO: populate items w/ 30 elements
[self.itemsCopy addObjectsFromArray:self.items];
//DO: remove all elements in items

Results

Begin Pass 1:
itemsCopy = 0
items = 30

End Pass 1:
itemsCopy = 30
items = 0

Begin Pass 2:
itemsCopy = 0
items = 30

End Pass 2:
itemsCopy = 30
items = 0

How can I constantly append items to the end of itemsCopy? I would like the scenario to look like this:

Begin Pass 1:
itemsCopy = 0
items = 30

End Pass 1:
itemsCopy = 30;
items = 0;

Begin Pass 2:
itemsCopy = 30
items = 30

End Pass 2:
itemsCopy = 60
items = 0

somewhere you must be re-initializing the itemsCopy array, or on each pass performing the operation on a different object.... — ennuikiller
– ennuikiller, Commented Jul 1, 2010 at 0:33
Sheehan Alam: Yes. See the documentation: developer.apple.com/iphone/library/documentation/Cocoa/…: Nowhere does it say that it will ever reset the array, nor is there any reason why it would. — Peter Hosey
– Peter Hosey, Commented Jul 1, 2010 at 12:05

Chuck · Accepted Answer · 2010-07-01 00:46:50Z

3

By keeping the same array you just filled in the itemsCopy property. It's clearly being reset to an empty array with whatever method you're using.

answered Jul 1, 2010 at 0:46

Chuck

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