I have a multi dimensional array which i need to convert to a list of arrays. Not one single array, but for each iteration of the first dimension i need a separate array containing the values in the second dimension.
How do I convert this:
int[,] dummyArray = new int[,] { {1,2,3}, {4,5,6}};
into a list<int[]> holding two arrays with values {1,2,3} and {4,5,6}?
You can convert 2d array into jagged array and then convert it to List.
int[,] arr = new int[,] { { 1, 2, 3 }, { 4, 5, 6 } };
int[][] jagged = new int[arr.GetLength(0)][];
for (int i = 0; i < arr.GetLength(0); i++)
{
jagged[i] = new int[arr.GetLength(1)];
for (int j = 0; j < arr.GetLength(1); j++)
{
jagged[i][j] = arr[i, j];
}
}
List<int[]> list = jagged.ToList();
You can use Linq:
int[,] dummyArray = new int[,] { { 1, 2, 3 }, { 4, 5, 6 } };
int count = 0;
List<int[]> list = dummyArray.Cast<int>()
.GroupBy(x => count++ / dummyArray.GetLength(1))
.Select(g => g.ToArray())
.ToList();
You could use for loop like this:
int[,] dummyArray = new int[,] { { 1, 2, 3 }, { 4, 5, 6 } };
int size1 = dummyArray.GetLength(1);
int size0 = dummyArray.GetLength(0);
List<int[]> list = new List<int[]>();
for (int i = 0; i < size0; i++)
{
List<int> newList = new List<int>();
for (int j = 0; j < size1; j++)
{
newList.Add(dummyArray[i, j]);
}
list.Add(newList.ToArray());
}
ToArray on list? you already know length, that not changed.Here is a reusable implementation
public static class Utils
{
public static List<T[]> To1DArrayList<T>(this T[,] source)
{
if (source == null) throw new ArgumentNullException("source");
int rowCount = source.GetLength(0), colCount = source.GetLength(1);
var list = new List<T[]>(rowCount);
for (int row = 0; row < rowCount; row++)
{
var data = new T[colCount];
for (int col = 0; col < data.Length; col++)
data[col] = source[row, col];
list.Add(data);
}
return list;
}
}
and sample usage
var source = new int[,] { { 1, 2, 3 }, { 4, 5, 6 } };
var result = source.To1DArrayList();
Some comments on other answers.
M.kazem Akhgary: If I need a list, I don't see why should I first create jagged array and convert it to a list instead of creating list directly.
Eser: I usually like his elegant Linq solutions, but this definitely is not one of them. If the idea is to use Linq (although I strongly believe it's not intended for that), the following would be much more appropriate:
var source = new int[,] { { 1, 2, 3 }, { 4, 5, 6 } };
var result = Enumerable.Range(0, source.GetLength(0))
.Select(row => Enumerable.Range(0, source.GetLength(1))
.Select(col => source[row, col]).ToArray())
.ToList();
List<int>he wantList<int[]>