按降序排序数组（NSArray） [英] Sorting array(NSArray) in descending order

问题描述

我有一个NSString对象数组，我必须通过降序排序。

I have a array of NSString objects which I have to sort by descending.

由于我没有找到任何API按降序排序数组我靠近

Since I did not find any API to sort the array in descending order I approached by following way.

我为下面列出的NSString写了一个类别。

I wrote a category for NSString as listed bellow.

- (NSComparisonResult)CompareDescending:(NSString *)aString
{

    NSComparisonResult returnResult = NSOrderedSame;

    returnResult = [self compare:aString];

    if(NSOrderedAscending == returnResult)
        returnResult = NSOrderedDescending;
    else if(NSOrderedDescending == returnResult)
        returnResult = NSOrderedAscending;

    return returnResult;
}

然后我使用语句对数组排序

Then I sorted the array using the statement

NSArray *sortedArray = [inFileTypes sortedArrayUsingSelector:@selector(CompareDescending:)];

这是正确的解决方案吗？有没有更好的解决方案？

Is this right solution? is there a better solution?

推荐答案

您可以使用NSSortDescriptor：

You can use NSSortDescriptor:

NSSortDescriptor* sortDescriptor = [NSSortDescriptor sortDescriptorWithKey:nil ascending:NO selector:@selector(localizedCompare:)];
NSArray* sortedArray = [inFileTypes sortedArrayUsingDescriptors:[NSArray arrayWithObject:sortDescriptor]];

这里我们使用 localizedCompare：字符串，并将 NO 传递到ascending：选项以按降序排序。

Here we use localizedCompare: to compare the strings, and pass NO to the ascending: option to sort in descending order.

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