组合多个元素集合的优雅方式? [英] Elegant way to combine multiple collections of elements?

问题描述

假设我有任意数量的集合，每个集合都包含相同类型的对象(例如，List foo 和 List bar).如果这些集合本身在一个集合中(例如，类型为 List>，我可以使用 SelectMany 将它们全部组合成一个集合.>

但是，如果这些集合不在同一个集合中，我的印象是我必须编写这样的方法:

public static IEnumerable;合并(参数ICollection[] toCombine){返回到Combine.SelectMany(x => x);}

然后我会这样称呼它:

var combine = Combine(foo, bar);

是否有一种干净、优雅的方式来组合(任意数量的)集合，而无需编写像上面的 Combine 这样的实用方法?看起来很简单，应该有一种方法可以在 LINQ 中做到这一点，但也许没有.

解决方案

我想您可能正在寻找 LINQ 的 .Concat()?

var combine = foo.Concat(bar).Concat(foobar).Concat(...);

或者，.Union() 将删除重复元素.

Say I have an arbitrary number of collections, each containing objects of the same type (for example, List<int> foo and List<int> bar). If these collections were themselves in a collection (e.g., of type List<List<int>>, I could use SelectMany to combine them all into one collection.

However, if these collections are not already in the same collection, it's my impression that I'd have to write a method like this:

public static IEnumerable<T> Combine<T>(params ICollection<T>[] toCombine)
{
   return toCombine.SelectMany(x => x);
}

Which I'd then call like this:

var combined = Combine(foo, bar);

Is there a clean, elegant way to combine (any number of) collections without having to write a utility method like Combine above? It seems simple enough that there should be a way to do it in LINQ, but perhaps not.

解决方案

I think you might be looking for LINQ's .Concat()?

var combined = foo.Concat(bar).Concat(foobar).Concat(...);

Alternatively, .Union() will remove duplicate elements.

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