CODEWITHSUNDEEP
c#.net
Helio Gracie
Helio Gracie

Reputation: 173

How to fill nested list

I have a nested list and I need his to fill the values ​​returned from the function. Is something like a two-dimensional matrix, where the number of rows is equal to the length of a list, and the number of columns of the length of another list. The question is how to call index to the elements of a nested list?

List<int> wordids;
List<int> hiddenids;
List<List<int>> inputWeights;

foreach (var wordid in wordids)
{
    foreach (var hiddeid in hiddenids)
    {
         inputWeights[wordid][hiddenid] = GetStrength(wordid, hiddenid);
    }
}

P.S. Sorry for my bad english.

Upvotes: 2

Views: 1077

Answers (4)

Matthew Watson
Matthew Watson

Reputation: 109547

You will need add lists to inputWeights as you go:

Using an outer foreach outer and an inner for loop:

var inputWeights = new List<List<int>>();

foreach (int wordid in wordids)
{
    var currentRow = new List<int>();

    for (int i = 0; i < hiddenids.Count; ++i)
        currentRow.Add(GetStrength(wordid, hiddenids[i]));

    inputWeights.Add(currentRow);
}

Using two foreach loops (this is my preferred solution, but opinions may differ!):

var inputWeights = new List<List<int>>();

foreach (int wordid in wordids)
{
    var currentRow = new List<int>();

    foreach (int hiddenid in hiddenids)
        currentRow.Add(GetStrength(wordid, hiddenid));

    inputWeights.Add(currentRow);
}

Or using Linq instead of the inner loop:

foreach (int wordid in wordids)
{
    var currentRow = new List<int>();
    currentRow.AddRange(hiddenids.Select(hiddenid => GetStrength(wordid, hiddenid)));
    inputWeights.Add(currentRow);
}

Or even using Linq for the entire thing (it's becoming unintelligible now ;):

var inputWeights = wordids.Select(
    wordid => new List<int>(hiddenids.Select(hiddenid => GetStrength(wordid, hiddenid)))
).ToList();

And just to be really complete, here's a solution using Linq Query Syntax (and yes, I spent too much time messing around with this, but I couldn't stop once I'd started... ;)

var inputWeights = (from wordid in wordids
                    select (from hiddenid in hiddenids
                            select GetStrength(wordid, hiddenid)).ToList()).ToList();

That's all assuming you actually want (#wordids * #hiddenids) in the results! Is that really true?

For example, if you have 10 wordids and 5 hiddenids, the output will have a total of 50 items.

Upvotes: 4

bash.d
bash.d

Reputation: 13207

In your particular case you shouldn't use foreach, but rather a usual for-loop, like 

List<int> wordids;
List<int> hiddenids;
List<List<int>> inputWeights;

wordids = new List<int>();
hiddenids = new List<int>();
inputWeights = new List<List<int>>();

//add values to your List-objects

foreach (int i = 0; i < wordids.Length; i++)
{
    foreach (int j = 0; j < hiddenids.Length; j++)
    {
         inputWeights[i][j] = GetStrength(wordids[i], hiddenids[j]);
    }
}

Upvotes: 1

zandi
zandi

Reputation: 704

List<List<int>> inputWeights=new List<List<int>>();

 for (var i = 1; wordids.Count > i; ++i)
 {
   for (var h = 1; hiddenids.Count > h; ++h)
   {
    inputWeights[i-1][h-1] = GetStrength(wordids[i-1], hiddenids[h-1]);
   }
 }

Upvotes: 0

David
David

Reputation: 16277

use two dimensional array or jagged array

int[][] jaggedArray = new int[3][];
jaggedArray[0] = new int[] { 1, 3, 5, 7, 9 };
jaggedArray[1] = new int[] { 0, 2, 4, 6 };
jaggedArray[2] = new int[] { 11, 22 };

a=jaggedArray[0][1];  //a=3;

Upvotes: 1

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