How to select random element from char array and assign it to list

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I have a char array(A) and int array(B). I want to select elements randomly from array A(selected elements have to be unique) and concatenate them with elements of array B from first element. Add the concatenated elements to a string list.
My problem is that selected elements aren't unique.

What I have tried:

C#

List<string> AB_Concat = new List<string>();
Random random = new Random();
for(int i=0;i<26;i++)
    AB_Concat.Add(Convert.ToString(A[random.Next(i, A.Length)]) + Convert.ToString(B[i]));

for (int i = 0; i < 26; i++)
   Console.Write(AB_Concat[i] + " ");

Posted 3-Nov-16 7:15am

NOSSAL

Updated 3-Nov-16 7:49am

Richard MacCutchan

v2

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Patrice T 3-Nov-16 13:43pm

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2 solutions

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OriginalGriff · Accepted Answer · 2016-11-03T07:43:00

If you need unique characters from Array A - i.e. it's similar to a pack of cards, you can only have one of each - then you need to remove each character from the input when you use it.
The simplest way to do that is to convert your array to a List and use RemoveAt each time:

C#

List<string> AB_Concat = new List<string>();
List<char> data = A.ToList();
Random random = new Random();
for (int i = 0; i < 26; i++)
    {
    int index = random.Next(data.Count);
    AB_Concat.Add(Convert.ToString(data[index]) + Convert.ToString(B[i]));
    data.RemoveAt(index);
    }
for (int i = 0; i < 26; i++)
    {
    Console.Write(AB_Concat[i] + " ");
    }

Richard MacCutchan · Accepted Answer · 2016-11-03T07:49:00

Solution 2

You need to use a collection that does not allow duplicates, such as the HashSet(T) Class (System.Collections.Generic)[^]. You will also then nedd to add code to keep adding until the set contains 26 items, rather than just iterating your list 26 times.

Posted 3-Nov-16 7:49am