Question

我有两个列表（List），其中包含以下数据：

列出一个

James
Jack
Laura
Harry

列出两个

Jeffery
Peters
Smith

是否可以使用Enumerable Join执行以下操作：

James Jeffery
James Peters
James Smith
Jack Jeffery
Jack Peters
Jack Smith
Laura Jeffery
Laura Peters
Laura Smith
Harry Jeffery
Harry Peters
Harry Smith
Harry Jeffery

这是什么类型的加入？

Answer 1

这是一个交叉联接：

List<string> textLines1 = new List<string>() {
    "Kames", "Jack", "Laura", "Harry"
};
List<string> textLines2 = new List<string>() {
    "Jeffery", "Peters", "Smith"
};

var query = from t1 in textLines1
            from t2 in textLines2
            select string.Format("{0} {1}", t1, t2);

var results = query.ToList();

返回您的期望。

也可以使用基于方法的查询来完成：

var query2 = textLines1.SelectMany(t1 => textLines2, (t1, t2) => string.Format("{0} {1}", t1, t2));

var results2 = query2.ToList();

Answer 2

在Linq，它将是：

List<string> TabOne = new List<string>() { "Kames", "Jack", "Laura", "Harry" };
List<string> TabTwo = new List<string>() { "Jeffery", "Peters", "Smith" }; 

var combo = from p in TabOne
        from c in TabTwo
        select new
        {
            Name = p,
            SurName = c
        };

它被称为交叉连接。

Answer 3

var l1 = new []{ "James", "Jack", "Laura", "Harry" };
var l2 = new []{ "Jeffery", "Peters", "Smith" };

var result = from i1 in l1
             from i2 in l2
             select i1 + " " + i2;

Answer 4

这也称为Cartesian Product，Eric有blog post about it。

Answer 5

您可以尝试这种方式：

var result = list1.SelectMany(i1 => list2.Select(i2 => i1 + " " + i2));

示例：

class Program
{
    public static void Main()
    {
        string[] list1 = new[] { "James", "Jack", "Laura", "Harry" };
        string[] list2 = new[] { "Jeffery", "Peters", "Smith" };
        var result = list1.SelectMany(i1 => list2.Select(i2 => i1 + " " + i2));

        foreach (string s in result)
        {
            Console.WriteLine(s);
        }
    }
}

App输出：

James Jeffery
James Peters
James Smith
Jack Jeffery
Jack Peters
Jack Smith
Laura Jeffery
Laura Peters
Laura Smith
Harry Jeffery
Harry Peters
Harry Smith

可数加入 - 加入两个列表

5 个答案: