可枚举连接 - 连接两个列表

Question

我有两个列表（列表）具有以下数据：

列表中的一个

James 
Jack 
Laura 
Harry 

列出两种

Jeffery 
Peters 
Smith 

是它可能使用Enumerable Join做一个Join，以执行以下操作：

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(); 

返回你所期望的。

它也可以使用基于查询的方法做：

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

var results2 = query2.ToList(); 

Answer 2

在LINQ这将是：

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 
     }; 

它被称为交叉联接。

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

这也被称为Cartesian Product和Eric有blog post about it。

Answer 5

你可以试试这个方法：

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

例子：

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