How to sort Dictionary on keys in c#

Question

I have a Dictionary that I want to sort by its keys.

var dict = new Dictionary<int, string>(){
    {1, "a"},
    {3, "c"},
    {2, "b"}
};

Converting it to a SortedDictionary alone doesn't work because I need the keys to be descending in value:

var sortedDict = new SortedDictionary<int, string>(dict);
foreach (var k in sortedDict)
{
    Console.WriteLine(k);
}

// Result:
[1, a]
[2, b]
[3, c]

// Desired result:
[3, c]
[2, b]
[1, a]

Is there any way to sort the Dictionary with a custom sorting option (like a lambda)?

SortedDictionary has a constructor where you can pass in an IComparer which should allow you to sort as you like. — Klaus Gütter, Nov 04 '20 at 15:45

score 2 · Accepted Answer · answered Nov 04 '20 at 15:46

2

var dict = new Dictionary<int, string>(){
  {1, "a"},
  {3, "c"},
  {2, "b"}
};

foreach (var k in dict.OrderByDescending(x => x.Key))
{
   Console.WriteLine(k);
}

answered Nov 04 '20 at 15:46

Pinx0

1,248
17
28

Yes but how do I convert a `System.Linq.IOrderedEnumerable>` back to a `Dictionary`? – max Nov 04 '20 at 15:51
1

You cannot without loss of sorting. A Dictionary is not sorted. – Klaus Gütter Nov 04 '20 at 15:57

How to sort Dictionary on keys in c#

1 Answers1