How to get reverse of a series of elements using Enumarable in C#?

问题

I have two Integer variables like

int Max = 10;
int limit = 5;

and a Dictionary

Dictionary<String , String> MyDict = new Dictionary<string,string>();

I need to fill the dictionary with Max elements and if the index is greater than or equal to limit then the value should be none.

Here is my sample code which will clear my question

int j = 1;
for (int i = Max-1; i >= 0; i--)
{
    if (i >= limit)
        MyDict.Add((j++).ToString(), "None");
    else
        MyDict.Add((j++).ToString(), i.ToString());
}

so the result will be like

{ "1" "None" }   
{ "2" "None" }   
{ "3" "None" }    
{ "4" "None" }
{ "5" "None" }
{ "6" "4" }
{ "7" "3" }
{ "8" "2" }
{ "9" "1" }
{ "10" "0" }

How to do this using LINQ or LAMBDA Expression

The reverse can be done using Enumarable here it is

MyDict  = Enumerable.Range(0, Max)
                    .ToDictionary(X => (X + 1).ToString(), X => X >= limit ? "None" : X.ToString());

Output of this expression

{ "1" "0" }
{ "2" "1" }
{ "3" "2" }
{ "4" "3" }
{ "5" "4" }
{ "6" "None" }
{ "7" "None" }
{ "8" "None" }
{ "9" "None" }
{ "10" "None" }

But how to do the reverse of this (like the output of the for loop)? Or how can I modify the existing LINQ?

Thanks in advance.

回答1:

Enumerable.Range(0, Max).OrderByDescending(x => x).ToDictionary(x => (Max - x).ToString(), x => x >= limit ? "None" : x.ToString());

来源：https://stackoverflow.com/questions/4123274/how-to-get-reverse-of-a-series-of-elements-using-enumarable-in-c