顺序整数升序和降序订单 [英] Order Integers In Ascending and Descending Orders

问题描述

我正与Objective-C的，但可能并不重要的编程语言这一点。所以基本上我有一个数组，也就是说，整数12，5，和17，而我希望能够拉出数量最多的，还是最小的，或第二小的，等等。

I'm working with Objective-C, but probably it doesn't matter the programming language for this. So basically I have an array, with say, the integers 12, 5, and 17, and I want to be able to pull out the largest number, or the smallest, or second smallest, etc.

基本上，我希望能够将它们分类到升序或降序排列，所以我可以挑出来，例如，第二小的数字通过检索 objectAtIndex：1 如果它是按升序排序。我觉得这是非常明显的，但我想不出如何在目前做到这一点，所以我会喜欢它，如果有人可以赐教。

Basically I want to be able to sort them into ascending or decending order so I could pick out, for instance, the second smallest number by retrieving the objectAtIndex: 1 if it is sorted in ascending order. I feel like this is incredibly obvious but I can't think of how to do it at the moment, so I would love it if someone could enlighten me.

推荐答案

如果你有一个的NSArray 与的NSNumber 实例，那么你正在寻找的排序是那么容易，因为这样的：

If you have an NSArray with NSNumber instances, then the sort you are looking for is as easy as this:

NSArray* sortedNumbers = [unorderedNumbers sortedArrayUsingSelector:@selector(intValue)];

这将排序上升，所以 [sortedNumbers lastObject] 将是最大的价值。

有关于的NSArray 更多的排序方法，如果你有更具体的要求。 <一href="http://developer.apple.com/library/mac/documentation/Cocoa/Reference/Foundation/Classes/NSArray_Class/NSArray.html#//apple_ref/doc/uid/20000137-SW12"相对=nofollow>的NSArray排序

There are many more sorting methods on NSArray if you have more specific needs. NSArray sorting

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