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  1. using System;
  2. using System.Collections.Generic;
  3. using System.Linq;
  4.  
  5. static class Program
  6. {
  7.     static void Main(string[] args)
  8.     {
  9.         var list1 = new int?[] {1, 2, 3, 4, 5};
  10.         var list2 = new int?[] {3, 4, 5, 6, 7};
  11.  
  12.         var joined = list1.FullOuterJoin(list2, a => a, b => b, (a, b, c) => new {list1=a, list2=b});
  13.  
  14.         joined.ToList().ForEach(Console.WriteLine);
  15.     }
  16. }
  17.  
  18. internal static class MyExtensions
  19. {
  20.     private static IDictionary<TK, IEnumerable<TV>> ToDictionary<TK,TV>(this IEnumerable<IGrouping<TK, TV>> grouping)
  21.     {
  22.         return grouping.ToDictionary(g => g.Key, g => g.AsEnumerable());
  23.     }
  24.  
  25.     private static IEnumerable<TV> OuterGet<TK, TV>(this IDictionary<TK, IEnumerable<TV>> dict, TK k, TV d=default(TV))
  26.     {
  27.         IEnumerable<TV> result;
  28.         return dict.TryGetValue(k, out result) ? result : new [] { d };
  29.     }
  30.  
  31.     internal static IList<TR> FullOuterJoin<TA, TB, TK, TR>(this IEnumerable<TA> a, 
  32.             IEnumerable<TB> b, 
  33.             Func<TA, TK> selectKeyA, Func<TB, TK> selectKeyB, 
  34.             Func<TA, TB, TK, TR> projection, 
  35.             TA defaultA=default(TA), TB defaultB=default(TB))
  36.     {
  37.         var adict = a.GroupBy(selectKeyA).ToDictionary();
  38.         var bdict = b.GroupBy(selectKeyB).ToDictionary();
  39.  
  40.         var keys = adict.Keys.Union(bdict.Keys);
  41.  
  42.         var join = from key in keys
  43.             from xa in adict.OuterGet(key, defaultA)
  44.             from xb in bdict.OuterGet(key, defaultB)
  45.             select projection(xa, xb, key);
  46.  
  47.         return join.ToList();
  48.     }
  49. }
  50.  
  51.  
Success #stdin #stdout 0.06s 37288KB
comments (?)
stdin 
Standard input is empty
stdout 
{ list1 = 1, list2 =  }
{ list1 = 2, list2 =  }
{ list1 = 3, list2 = 3 }
{ list1 = 4, list2 = 4 }
{ list1 = 5, list2 = 5 }
{ list1 = , list2 = 6 }
{ list1 = , list2 = 7 }
https://ideone.com/mFLYhT
language:
C# (gmcs 5.20.1)
created:
12 years ago
visibility:
secret

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