有一个整齐的LINQ的方式来'联盟'一个项目？ [英] Is there a neater linq way to 'Union' a single item?

问题描述

如果我有两个序列，我要处理他们两个在一起，我可以联合他们，我们就走了。

If I have two sequences and I want to process them both together, I can union them and away we go.

现在可以说我有我想两者之间sequencs处理一个项目。我可以通过创建一个单一的项目数组得到它，但有一个更合适的方法？ 。即

Now lets say I have a single item I want to process between the two sequencs. I can get it in by creating an array with a single item, but is there a neater way? i.e.

var top = new string[] { "Crusty bread", "Mayonnaise" };
string filling = "BTL";
var bottom = new string[] { "Mayonnaise", "Crusty bread" };

// Will not compile, filling is a string, therefore is not Enumerable
//var sandwich = top.Union(filling).Union(bottom);

// Compiles and works, but feels grungy (looks like it might be smelly)
var sandwich = top.Union(new string[]{filling}).Union(bottom);

foreach (var item in sandwich)
    Process(item);

是这样做有一个批准的方式，或者是这个批准方法是什么？

Is there an approved way of doing this, or is this the approved way?

感谢

推荐答案

一种选择是自己超负荷

public static IEnumerable<T> Union<T>(this IEnumerable<T> source, T item)
{
    return source.Union(Enumerable.Repeat(item, 1));
}

这就是我们所做的与的 的毗连 中的 moreLINQ 。

That's what we did with Concat in MoreLINQ.

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