Writing list to CSV file

Question

I have a List of List of int called NN which i would like to write to a csv file like this:

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

The NN list:

1,2,3,4,5,6
2,5,6,3,1,0
0,9,2,6,7,8

And the output csv file should look like this:

1,2,0
2,5,9
3,6,2
4,3,6
5,1,7
6,0,8

What is the best way to achieve that?

If there is a better representation you would recommend instead of the nested list i'll be glad to know.

(The purpose is that each list of int is the weights between the last and next layer in the neural network).

Answer 1

Here is how you can do it:

List<List<int>> NN = new List <List<int>>
{
    new List<int> {1,2,3,4,5,6},
    new List<int> {2,5,6,3,1,0},
    new List<int> {0,9,2,6,7,8}
};

//Get expected number of rows
var numberOfRows = NN[0].Count; 

var rows =
    Enumerable.Range(0, numberOfRows) //For each row
    .Select(row => NN.Select(list => list[row]).ToList()) //Get row data from all columns
    .ToList();

StringBuilder sb = new StringBuilder();

foreach (var row in rows)
{
    sb.AppendLine(string.Join(",", row));
}

var result = sb.ToString();