I have a multidimensional double array with any number of rows and columns:
var values = new double[rows, columns];
I also have a list of double arrays:
var doubleList = new List<double[]>();
Now, I would like to add each column in the multidimensional array to the list. How do I do that? I wrote this to illustrate what I want, but it does not work as I am violation the syntax.
for (int i = 0; i < columns; i++)
{
doubleList.Add(values[:,i];
}
var values = new double[rows, columns];
var doubleList = new List<double[]>();
for (int i = 0; i < columns; i++)
{
var tmpArray = new double[rows];
for (int j = 0; j < rows; i++)
{
tmpArray[j] = values[j, i];
}
doubleList.Add(tmpArray);
}
You will need to create a new array for each column and copy each value to it.
Either with a simple for-loop (like the other answers show) or with LINQ:
for (int i = 0; i < columns; i++)
{
double[] column = Enumerable.Range(0, rows)
.Select(row => values[row, i]).ToArray();
doubleList.Add(column);
}
doubleList=Enumerable.Range(0,columns).Select(col=>Enumerable.Range(0,rows).Select(row=>values[row,col]).ToArray()).ToList(); if you really hate for loops.var doubleList = (from c in Enumerable.Range(0, columns) select (from r in Enumerable.Range(0, rows) select values[r, c]).ToArray()).ToList(); ;)With the approach you were taking:
for(int i = 0; i != columns; ++i)
{
var arr = new double[rows];
for(var j = 0; j != rows; ++j)
arr[j] = values[j, i];
doubleList.Add(arr);
}
Build up the each array, per row, then add it.
Another approach would be:
var doubleList = Enumerable.Range(0, columns).Select(
i => Enumerable.Range(0, rows).Select(
j => values[j, i]).ToArray()
).ToList()
Which some would consider more expressive in defining what is taken (values[j, i] for a sequence of i inner sequence of j) and what is done with them (put each inner result into an array and the result of that into a list).
