Trying to convert an int[] into int[,] using C#
I would like a function to convert a single dimension array int[480000] into a 2d array of size int[800,600]. Can you please help me how this c开发者_如何学运维an be done?
public static T[,] Convert<T>(this T[] source, int rows, int columns)
{
int i = 0;
T[,] result = new T[rows, columns];
for (int row = 0; row < rows; row++)
for (int col = 0; col < columns; col++)
result[row, col] = source[i++];
return result;
}
Do you really want to physically move the data or would a 800x600 'View' be sufficient?
You could use a wrapper like this:
// error checking omitted
class MatrixWrapper<T>
{
private T[] _data;
private int _columns;
public MatrixWrapper(T[] data, int rows, int columns)
{
_data = data;
_columns = columns;
// validate rows * columns == length
}
public T this[int r, int c]
{
get { return _data[Index(r, c)]; }
set { _data[Index(r, c)] = value; }
}
private int Index(int r, int c)
{
return r * _columns + c;
}
}
And you use it like:
double[] data = new double[4800];
var wrapper = new MatrixWrapper<double>(data, 80, 60);
wrapper[2, 2] = 2.0;
for (int i = 0; i < 800; ++i) {
for (int j = 0; j < 600; ++j) {
m[i, j] = a[600*i + j];
}
}
Depending on your storage layout, you might need to use i + 800*j
instead.
UPD (fixed filling by column instead of by row, here is right version)
private static T[,] create2DimArray<T>(T[] array, int n)
{
if (n <= 0)
throw new ArgumentException("Array M dimension cannot be less or equals zero","m");
if (array == null)
throw new ArgumentNullException("array", "Array cannot be null");
if (array.Length == 0)
throw new ArgumentException("Array cannot be empty", "array");
int m = array.Length % n == 0 ? array.Length / n : array.Length / n + 1;
var newArr = new T[m,n];
for (int i = 0; i < arr.Length; i++)
{
int k = i / n;
int l = i % n;
newArr[k, l] = array[i];
}
return newArr;
}
For 1000000 of elements it works 33 ms on my machine. Really fast with 1 for
loop.
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