objective-c - 如何恢复 NSMutableArray 的原始排序顺序？

Question

我已经将一个 NSString 标记化为一个 NSMutable 数组。然后我可以使用 NSSortDescriptor 按字符串的长度对该数组进行排序。然后我可以从最长的开始对某些单词执行方法。

这就是我的问题所在。我现在需要恢复数组的原始排序顺序，以便我可以将数组运行回已编辑的字符串。

Answer 1

我的回答基本上和 Steve 的一样，只是我会以相反的方式来做 — 保留原始数组，创建它的排序副本，逐步执行处理的排序副本，然后将其丢弃。所以，例如

NSArray *yourOriginalArray = ...whatever...;

// do processing
for(id object in [yourOriginalArray sortedArrayUsing<whatever means>])
{
    // if you're doing processing that doesn't change the identity of
    // the object then there's no need to worry about this, but supposing
    // you want to adjust the identity (eg, the source array is full of
    // immutable objects and you want to replace them) then...

    NSUInteger originalIndex = [yourOriginalArray indexOfObject:object];

    id replacementObject = [self mutatedFormOf:object];
    [yourOriginalArray replaceObjectAtIndex:originalIndex
                     withObject:replacementObject];
    // of course, this is only if yourOriginalArray is mutable
}