Sort collection by another collection values

问题:

I have List<SomeData> data;

public class SomeData {     public int Key { get; set;}     public decimal Value { get; set;} } 

Also i have List<int> DataOrder;

I need to sort List<SomeData>data by Key, placing it in same order as List<int> DataOrder values.

Is there any common algorithms for that?

Example:

List<SomeData> data = new List<SomeData>(); data.Add(new SomeData{ Key = 10, Value = 14 }) data.Add(new SomeData{ Key = 25, Value = 22 }) data.Add(new SomeData{ Key = 567, Value = 3 }) data.Add(new SomeData{ Key = 57, Value = 300 }) data.Add(new SomeData{ Key = 17, Value = 200 }) data.Add(new SomeData{ Key = 343, Value = 42 })  List<int> DataOrder = new List<int>{1, 25, 700, 567, 343, 350, 10}; 

Result after sorting:

foreach(var element in data) {      Console.WriteLine(element.Key); } 

Out:

25 567 343 10 57 17 

Edit: initial data array can have Key, that not contain in DataOrder Such value should be placed at the end of result collection in any order. Example changed to illustrate it.

回答1:

What about joining:

var mySortedList = (from i in DataOrder             join d in data on i equals d.Key             select new SomeData              {                  Key = d.Key,                  Value = d.Value              }); 

EDIT: To also add those values from data that do NOT share any key within the DataOrder-list you may simply add a Union to the result as follows:

var result = mySortedList.Union(data.Where(x => !DataOrder.Contains(x.Key))); 

回答2:

Solved

public class SomeData {     public int Key { get; set; }     public decimal Value { get; set; } }  class Program {     static void Main(string[] args)     {         List<SomeData> orders = new List<SomeData>();          orders.Add(new SomeData { Key = 10, Value = 14 });         orders.Add(new SomeData { Key = 25, Value = 22 });         orders.Add(new SomeData { Key = 567, Value = 3 });         orders.Add(new SomeData { Key = 57, Value = 300 });         orders.Add(new SomeData { Key = 17, Value = 200 });         orders.Add(new SomeData { Key = 343, Value = 42 });          List<int> ids = new List<int> { 1, 25, 700, 567, 343, 350, 10 };          //get orders only from ids with order         List<SomeData> existedOrders = (from order in orders                                         join id in ids                                              on new { onlyId = order.Key }                                             equals new { onlyId = id }                                         orderby ids.IndexOf(id)                                         select order).ToList();          //add others         existedOrders.AddRange(orders.Except(existedOrders).ToList());      } } 

//with @HimBromBeere solution you can reduce query

//get orders only from ids with order List<SomeData> existedOrders = (from order in orders                                 join id in ids                                      on order.Key equals id                                 orderby ids.IndexOf(id)                                 select order).ToList(); 

回答3:

int count = 0; for(int i in DataOrder) {     var index = data.IndexOf(d => d.Key == i);     swap(data[count], data[index]);     count++; } 

and swap function is for swap places of items.

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