Get objects at index out of List<Object> - c#

I'm trying to make a 2D RPG game, and would like to use a List< List< Object > > to make a grid in which I store world objects of different types. Only problem is, that I don't know how to get stuff out of this multidimensional List.
The code below creates a multidimensional List and fills it with 'Dirt' Objects (though objects[i] doesnt work, which is my problem).
public List<List<Object>> objects;
this.mapWidth = 36;
this.mapHeight = 21;
this.objects = new List<List<Object>>();
for (int y = 0; y < mapHeight; y++)
{
objects.Add(new List<Object>());
}
for (var i = 0; i < mapWidth; i++)
{
for (var j = 0; j < mapHeight; j++)
{
objects[i].Add(new Dirt());
}
}
The players has a position, e.g. 18,11, which is in the middle of this map/multidimensional List. I would like to check which 'tiles' are around him so I only have to update those things on the map. List[y][x] doesnt work.

I think your initial construction code is incorrect. Looks like you're building your grid to have mapHeight rows and mapheight columns. Rewrite the construction code to be this:
for (var y = 0; y < mapHeight; y++)
{
objects.Add(new List<Object>());
for (var x = 0; x < mapWidth; x++)
{
objects[y].Add(new Dirt());
}
}
EDIT: And I think this will produce a table where your lookup can be achieved by: Object gridEntry = objects[y][x];
EDITx2: If you like, you can rewrite the creation code to this:
for (var y = 0; y < mapHeight; y++)
{
List<Object> currentRow = new List<Object>();
objects.Add(currentRow);
for (var x = 0; x < mapWidth; x++)
{
currentRow.Add(new Dirt());
}
}

Related

Index out of range for multi dimensional array

I'm getting the error that the index for my array is out of range.
I define a 3D array like this:
Button[, ,] posAr_ItemManager = new Button[maxRows, maxColumns, maxCategories];
Where maxRows, maxColumns and maxCategories are all constant integers.
I then want to loop through this whole array, i do it using nested loops as shown here:
for (int i = 0; i < posAr_ItemManager.GetLength(0); i++)
{
for (int j = 0; i < posAr_ItemManager.GetLength(1); j++)
{
for (int z = 0; i < posAr_ItemManager.GetLength(2); z++)
{
if (posAr_ItemManager[i,j,z] != null)
{
Button but = posAr_ItemManager[i, j, z];
but.Width = itemWidth;
but.Height = itemHeight;
but.SetValue(Canvas.LeftProperty, itemPanelX + (i + 1) * butSpacing + i * itemWidth);
but.SetValue(Canvas.TopProperty, itemPanelY + (i+1)*butSpacing + i* itemHeight);
}
}
}
}
When I run the program it gives the out of range error where I check if the item is not equal to null.
I have no idea why it does it as I thought my declaration of the 3D array is correct and the nested loop as well? thanks in advance!
for (int i = 0; i < posAr_ItemManager.GetLength(0); i++)
{
for (int j = 0; j < posAr_ItemManager.GetLength(1); j++)
{
for (int z = 0; z < posAr_ItemManager.GetLength(2); z++)
look very carefully at the middle tests. Also, consider hoisting the GetLength tests so you only do them once per dimension. Perhaps:
int rows = posAr_ItemManager.GetLength(0), columns = posAr_ItemManager.GetLength(1),
categories = posAr_ItemManager.GetLength(2);
for (int row = 0; row < rows; row++)
{
for (int col = 0; col < columns; col++)
{
for (int cat = 0; cat < categories; cat++)
You're using "i" to check if the loop is over in each of the dimensions. Change it to corresponded i,j,z.
for (int i = 0; i < posAr_ItemManager.GetLength(0); i++)
{
for (int j = 0; **j** < posAr_ItemManager.GetLength(1); j++)
{
for (int z = 0; **z** < posAr_ItemManager.GetLength(2); z++)

C# - How to initialize multiple variables in a loop

I figured out how to do this with VBA.
Dim variable(1 To 10) As Variant
I am having a tough time figuring out how to do this with C#. Here is what I have that does not work:
for (int y = 0; y < 10; y++)
{
List<List<string>> row(y) = new List<List<string>>();
}
Any help would be appreciated.
If I understand your purpose correctly, you're trying to do this:
List<List<string>> row = new List<List<string>>(10);
for (int y = 0; y < 10; y++)
{
row.Add(new List<string>());
}
This will create a list of 10 List<string> objects and initialize each element with a new List<string> object.
Edit
After seeing your latest comment, you need this:
var rows = new List<List<string>>[10];
for (int y = 0; y < 10; y++)
{
rows[y] = new List<List<string>>();
}
Couple of ways this can be done, using a List of List<string> :
List<List<string>> list = new List<List<string>>();
for (int y = 0; y < 10; y++)
{
list.Add(new List<string>());
}
Using an array of List<string>
List<string>[] array = new List<string>[10];
for (int y = 0; y < 10; y++)
{
array[y] = new List<string>();
}

Show sublist value from index C#

My problem is I have M subproblem. Each subproblem include x (double array) and reduced cost which has different value for each iteration m. I want to show x which has the minimum reduced cost among all subproblems. here is my class:
public class Subproblem
{
public double[,] x { get; set; }
public double ReducedCost { get; set; }
}
So far, I already can get the minimum Reduced Cost and index of it. Now I want to show x value (double array) which on that index. I've code like this:
var sub = new List<Subproblem>();
for (int m = 0; m < M; ++m)
{
Subproblem s = new Subproblem();
s.x = new double[DC1, DC1];
s.ReducedCost = model.ObjVal;
for (int i = 0; i < DC1; ++i)
{
for (int j = 0; j < DC1; ++j)
{
s.x[i, j] = x[i, j].X;
}
}
sub.Add(s);
}
double minRC = sub.Min(a => a.ReducedCost);
int minRCIndex = sub.FindIndex((i) => i.ReducedCost == minRC);
Console.WriteLine(sub.x(minRCIndex));
the last line (Console.WriteLine(sub.x(minRCIndex));) still got red underline, I don't know how to write it
If you are only trying to get the minimum Reduced Costed subproblem you should be doing:
Subproblem minimumReducedCostedSubproblem = sub[minRCIndex];
And you can print the matrix down like this:
for (int i = 0; i < DC1; ++i)
{
for (int j = 0; j < DC1; ++j)
{
Console.Write(minimumReducedCostedSubproblem.x[i, j] + "\t");
}
Console.Write("\n");
}
But you seem a little confused. You are pushing a Subproblem into your sub list with the same object for M times. Because model.ObjVal doesn't change along the first for loop. There is something wierd going on there too.
It should be
var objWithMinReduceCost = sub[minRCIndex];
//Now you have the object of Subproblem derived from your logic.
//You can access x property of it have further logic to process it.
for (int i = 0; i < DC1; ++i)
{
for (int j = 0; j < DC1; ++j)
{
Console.WriteLine(objWithMinReduceCost.x[i, j]);
}
}
If you are interested in obtaining the double array, you could just do this:
double[,] result = sub.First(i => i.ReducedCost == minRC).x;
Although as Tolga mentioned, all your elements will have the same ReducedCost with your current code.

How to print C# 3D jagged array

From #Henk Holterman's response regarding C# 3 dimensional arrays (answered Mar 29 '09 at 12:05), how do you print foos to the console:
Foo[][][] foos = new Foo[2][][];
for (int a = 0; a < foos.Length; a++)
{
foos[a] = new Foo[3][];
for (int b = 0; b < foos[a].Length; b++)
{
foos[a][b] = new Foo [4];
for (int c = 0; c < foos[a][b].Length; c++)
foos[a][b][c] = new Foo();
}
}
Thanks.
This is fairly simple to do. Use three for statements to loop through each indexer to get to each instance of Foos.
for (int x = 0; x < foos.Length; x++) {
for (int y = 0; y < foos[x].Length; y++) {
for (int z = 0; z < foos[x][y].Length; z++) {
Console.WriteLine(foos[x][y][z].Member);
}
}
}

How to assign value in two dimensional array

How to assign value in two dimensional array in c#
My Code is
int[,] matarix = new int[4, 5];
for (int x = 0; x < 4; x++)
{
for (int y = 0; y < 5; y++)
{
matarix[x, y] = x+"-"+y;
}
}
i tried above code but its showing error "can't implicitly convert string to int"
How to do it ? Thanks
You're on the right track. Just assign a value.
int[,] matarix = new int[4, 5];
for (int x = 0; x < 4; x++) {
for (int y = 0; y < 5; y++) {
matarix[x, y] = VALUE_HERE;
}
}
One recommendation I would make, would be to use Array.GetLength instead of hard coding your for loops. Your code would become:
int[,] matarix = new int[4, 5];
for (int x = 0; x < matarix.GetLength(0); x++) {
for (int y = 0; y < matarix.GetLength(1); y++) {
matarix[x, y] = VALUE_HERE;
}
}
You pass in one of the array's dimensions, and it tells you how many indices exist for that dimension.
This is a template I usually use for filling up two dimensional arrays.
Its one line and easy to change.
int[,] Foo = new int[4,5];
for(int i=0;i < Foo.Length; i++, Foo[i % Foo.GetLength(0),i / Foo.GetLength(1)] = 0; // Or value to assign
Also please do note that your array is holding integers while you are giving it strings (the "" converts it to a string, while x - y keeps it integer)
Hope it helps

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