你如何深拷贝一个多维的NSMutableArray及其内容？ [英] How do you deep copy a multidimensional NSMutableArray and its contents?

问题描述

我现在有一个三维的NSMutableArray，我需要深拷贝。然而，现在看来，以下code使它和它的内容，当我试图从它删除任何对象成为不可变的，因为它会导致NSInvalidArgumentException。

I currently have a three dimensional NSMutableArray which I need to deep copy. However, it appears that the following code causes it and its contents to become immutable, since it causes NSInvalidArgumentException when I attempt to remove any objects from it.

NSMutableArray* copy = [[[NSMutableArray alloc] initWithArray:input copyItems:YES] autorelease];

我怎么能不深导致它成为不可改变复制一个数组？

How can I deep copy an array without causing it to become immutable?

推荐答案

从上市，

不变类的副本imlementation通常返回相同
  对象 - 因为它是不可变的没有必要有一个真实
  复制。但你不必担心这一点。

The copy imlementation of immutable classes usually returns the same object - because it's immutable there is no need to have a "real" copy. But you don't have to worry about this.

从以上 http://lists.apple.com/档案/可可开发/ 2008 /月/ msg00172.html

因此​​，请确保您添加在你的输入数组，即输入数组转换成可变的副本，然后调用该方法。

So make sure before you add your input array, convert that input array into a mutable copy and then call the method.

NSMutableArray* mutableInput = [input mutableCopy];
NSMutableArray* copy = [[[NSMutableArray alloc] initWithArray:mutableInput copyItems:YES]autorelease];

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