copy NSArray inside an empty NSArray

Question

I have a first NSArray firstArray and I do

[firstArray removeAllObjects];

after I want fill it with the content of an other array secondArray

is it right write in this way?

firstArray = secondArray;

Joshua Weinberg · Accepted Answer · 2011-06-14 13:53:57Z

1

No, firstArray = secondArray will reassign the pointers, this is not the behavior you want. You want [firstArray addObjectsFromArray:secondArray]

answered Jun 14, 2011 at 13:53

Joshua Weinberg

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3 Comments

and if I use initwitharray? what happens?

You'd be breaking the contract of the object. Objects must only be initialized once, doing it multiple times WILL cause you problems down the road.

@JoshuaWeinberg What about firstArray = [secondArray copy];?

BP. · Accepted Answer · 2011-06-14 13:56:29Z

1

Since the firstArray is an NSArray, you will want to do this instead:

firstArray = [NSArray arrayWithArray:secondArray];

answered Jun 14, 2011 at 13:56

BP.

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and if it's a nsMutableArray?

If firstArray is an NSMutableArray, you can use the addObjectsFromArray method that Joshua suggested.