列表的交集 [英] Intersection of lists

问题描述

是否有更好，更优雅和简洁的方法来获取C#中两个列表的交集?

Is there a better, more elegant and concise, way to get the intersection of two lists in C#?

在C#中，一种计算日期列表交集的方法是:

In C# a method to calculate an intersection of list of dates is:

    public List<DateTime> dates_common(Timeserie ts1, Timeserie ts2)
    {
        var dt1 = new HashSet<DateTime>(ts1.dates);
        var dt2 = new HashSet<DateTime>(ts2.dates);
        dt1.IntersectWith(dt2);
        var dt = new DateTime[dt1.Count];
        dt1.CopyTo(dt);
        return new List<DateTime>(dt);
    }

在Ruby中，这样做是:

In Ruby one would do this as:

def dates_common(ts1, ts2)
    dt1 = ts1.dates.to_set    
    dt2 = ts2.dates.to_set
    return dt1.intersection(dt2).to_a
end

这种笨拙的根本原因是IEnumerable与具体容器和数组之间的不对称性.

The root cause of this clunkiness is the asymmetry between IEnumerable and concrete containers and arrays.

我一直惊讶于C#标准库的设计多么糟糕，因为这种问题一直在出现.

I am constantly amazed how badly designed C# standard libraries are as this kind of problems come up all the time.

有没有更好的方法，这意味着更优雅，更简洁的方法呢?

Is there a better, this means more elegant and concise, way to do this?

推荐答案

您可以使用 Enumerable.Intersect 和 Enumerable.ToList

You can use the Enumerable.Intersect and Enumerable.ToList extension methods as follows to get very elegant and concise code:

public List<DateTime> dates_common(Timeserie ts1, Timeserie ts2)
{
    return ts1.dates.Intersect(ts2.dates).ToList();
}

这篇关于列表的交集的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！