使用LINQ交換列表值

Question

我想按照下面的說明交換列表。我想保留一些元素值（不是全部）從「主」換到「次」的列表數。

namespace listswap 
{ 

    public class emp 
    { 
     public int id { get; set; } 
     public string primary { get; set; } 
     public string fName { get; set; } 
     public string lName { get; set; } 
     public string state { get; set; } 
     public string country { get; set; } 
    } 
    class Program 
    { 
     static void Main(string[] args) 
     { 
      var empList = new List<emp>(); 
     empList.AddRange(new emp[] { new emp {primary = "Yes", id = 1, fName = "Vivek", lName = "Ranjan", state = "TN", country = "India"}, 
            new emp { primary = "No", id = 2, fName = "Deepak", lName = "Kumar", state = "AP", country = "UK"}, 

     }); 


      /* Desired list :  
      No of list 1 with two elements    
      empList[0]. primary = "Yes", id = 1, fName = "Vivek", lName = "Ranjan", state = "TN", country = "India" 
      empList[1]. primary = "No", id = 2, fName = "Vivek", lName = "Ranjan", state = "TN", country = "India" 

      */ 
     } 
    } 
} 

Answer 1

這是基礎知識和簡單：

var l1 = empList.Where(c=>c.primary == "Yes").ToList(); 
var l2 = empList.Where(c=>c.primary == "No").ToList(); 

對於列出的清單：

var result = empList.GroupBy(c => c.primary).Select(c => c.ToList()).ToList(); 

編輯：

var primary = empList.FirstOrDefault(c => c.primary == "Yes"); 

var r = empList.Select(c => new emp 
{ 
    primary = c.primary, 
    id = c.id, 
    fName = primary != null ? primary.fName : c.fName, 
    lName = primary != null ? primary.lName : c.lName, 
    state = primary != null ? primary.state : c.state, 
    country = primary != null ? primary.country : c.country 
}).ToList();