假设我有一个二维浮点数数组
float [,] myfloats = new float[10, 10]
FillWithValues(myfloats);
我该如何使用随机评估方法将这个二维浮点数数组转换为一个二维布尔数组?
我希望可以做到以下这样:
bool[,] mybools;
mybools = myfloats.Select(myfloat => Evaluate(myfloat));
但这并不起作用...
假设我有一个二维浮点数数组
float [,] myfloats = new float[10, 10]
FillWithValues(myfloats);
bool[,] mybools;
mybools = myfloats.Select(myfloat => Evaluate(myfloat));
但这并不起作用...
很遗憾,多维数组与LINQ不兼容且难以处理。我认为没有绕过这个双循环解决方案的方法:
bool[,] mybools = new bool[myfloats.GetLength(0), myfloats.GetLength(1)];
for (int x = 0; x<myfloats.GetLength(0); x++)
for(int y=0; y<myfloats.GetLength(1); y++)
mybools[x,y] = Evaluate(myfloats[x,y]);
Array.GetLength(Int32)
方法可以返回数组在特定维度上的大小。
var floats = new float[3, 3] {
{ 1f, 2f, 3f },
{ 4f, 5f, 6f },
{ 7f, 8f, 9f }
};
Func<float, bool> floatToBool = f => f > 5f;
var bools =
floats
.ToJaggedArray()
.Select(array => array.Select(floatToBool).ToArray())
.ToArray()
.To2DArray();
var bools =
floats
.ToEnumerableOfEnumerables()
.Select(array => array.Select(floatToBool))
.To2DArray();
[Pure, NotNull]
public static T[][] ToJaggedArray<T>([NotNull] this T[,] p2DArray) {
var height = p2DArray.GetLength(0);
var width = p2DArray.GetLength(1);
var result = new T[height][];
for (var row = 0; row < height; row++) {
result[row] = new T[width];
for (var col = 0; col < width; col++)
result[row][col] = p2DArray[row, col];
}
return result;
}
[Pure, NotNull]
public static T[,] To2DArray<T>([NotNull] this T[][] pJaggedArray) {
if (!pJaggedArray.Any() || !pJaggedArray[0].Any())
return new T[0, 0];
var height = pJaggedArray.Length;
var width = pJaggedArray[0].Length;
var result = new T[height, width];
for (var r = 0; r < height; r++) {
var subArray = pJaggedArray[r];
if (subArray == null || subArray.Length != width)
throw new InvalidOperationException("Jagged array was not rectangular.");
for (var c = 0; c < width; c++)
result[r, c] = subArray[c];
}
return result;
}
And for the second part are something like this:
[Pure, NotNull]
public static IEnumerable<IEnumerable<T>> ToEnumerableOfEnumerables<T>(
[NotNull] this T[,] p2DArray
) {
var height = p2DArray.GetLength(0);
for (var row = 0; row < height; row++)
yield return p2DArray.GetPartialEnumerable(row);
}
[Pure, NotNull]
public static IEnumerable<T> GetPartialEnumerable<T>(
[NotNull] this T[,] p2DArray,
int pRow
) {
var width = p2DArray.GetLength(1);
for (var col = 0; col < width; col++)
yield return p2DArray[pRow, col];
}
[Pure, NotNull]
public static T[,] To2DArray<T>(
[NotNull] this IEnumerable<IEnumerable<T>> pJaggedArray
) {
if (!pJaggedArray.Any() || !pJaggedArray.First().Any())
return new T[0, 0];
var height = pJaggedArray.Count();
var width = pJaggedArray.First().Count();
var result = new T[height, width];
var r = 0;
foreach (var subArray in pJaggedArray) {
if (subArray == null || subArray.Count() != width)
throw new InvalidOperationException("Jagged array was not rectangular.");
var c = 0;
foreach (var item in subArray)
result[r, c++] = item;
r += 1;
}
return result;
}
Enumerable.Range(0, n).Select(x => Enumerable.Range(0, m).Select(y => (stuff[x, y] = (x * y)) > 10).ToArray()).ToArray();
- 你可以通过这种方式既返回新数组,又将值分配给现有数组(建议使用ToList()/ToArray()来实际执行可枚举)。当然,返回类型将是[n][m],而不是[n,m],因为在这种情况下不应使用LINQ ;) - PTwr