返回唯一值，而不删除重复 - C＃ [英] Return unique values without removing duplicates - C#

问题描述

我知道大约有删除重复后的数组返回唯一值很多答案，但不是每个数组中的元素独特的你删除重复后？我想是唯一的值删除任何重复之前只返回。如果元素原始数组中重复，我不想在我的最后一个数组。

I know there are many answers about returning unique values in an array after removing duplicates, but isn't every element in an array unique after you remove the duplicates? I want to only return values that are unique prior to removing any duplicates. If the element repeats in the original array, I don't want it in my final array.

所以这阵...

[0, 1, 1, 2, 3, 3, 3, 4]

应该只返回：

[0, 2, 4]

另一种表达，这将是删除所有重复，以及那是有史以来所有的唯一值复制。

Another way to phrase this would be to remove all duplicates as well as all unique values that were ever duplicates.

我是从一个JavaScript背景的和我还是有点不稳与C＃语法。 ：）

I'm coming from a JavaScript background and am still a little shaky with C# syntax. :)

推荐答案

的最简单的方法是使用LINQ，由值分组，各组中的计数元件的数量，然后返回键基与单个值

The simplest approach is to use LINQ, grouping by the value, counting the number of elements in each group, and then returning the keys for groups with a single value:

var singleOccurrences = array.GroupBy(x => x)
                             .Where(g => g.Count() == 1)
                             .Select(g => g.Key)
                             .ToArray();

如果你真的需要这是高效的为大投入，你可以写和元素与多个值为集跟单值元素你自己的方法保持跟踪。我开始与这虽然：）

If you really need this to be efficient for large inputs, you could write your own method keeping track of "elements with a single value" and "elements with more than one value" as sets. I'd start with this though :)

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