Array with negative indexes

Question

I have an array which I\'m using to store map data for a game I\'m working on.

MyMapType[,,] map; 

The reason I\'m using a fixed array inst

Answer 1

Use the Dictionary class, since you can assign whatever values you want for either the key or value. While I'm not sure how this would work for the 3-dimensional array that you showed above, I can show how this would work if this were a 1-dimensional array, and you can infer how to best make use of it:

MyMapType[] map;

//map is filled with w/e data

Dictionary<int, MyMapType> x = new Dictionary<int, MyMapType>();

x[-1] = //(map data for whatever value is for the negative value);
x[0] = map[0]
//(etc...)

Answer 2

I'd like to note here that dictionaries allow for negative indexes and a 2D dictionairy can solve problems like these too, just think about the datastructure and if you can live with a dictionary

note that dictionaries and lists are used in different scenario's. and their speed depends on what functions are used on them

Answer 3

If you want "negative" indexes C# 8 now supports it.

var words = new string[]
{
                // index from start    index from end
    "The",      // 0                   ^9
    "quick",    // 1                   ^8
    "brown",    // 2                   ^7
    "fox",      // 3                   ^6
    "jumped",   // 4                   ^5
    "over",     // 5                   ^4
    "the",      // 6                   ^3
    "lazy",     // 7                   ^2
    "dog"       // 8                   ^1
};              // 9 (or words.Length) ^0

So the to call the negative one would be like this

words[^1]

See this link

So in your case the middle element could be the zero Z

Answer 4

Could you try to store a list of MyMapTime[,] in two lists:

• one for z values of greater than or equal to 0
• and second of negative z-values.

The index of the tables would be the value of z. Having this would let you access quickly the xy-values for specific z-level. Of course the question is: what are your z-values? Are there sparse or dense. Even for sparse values you would end up with an array holding null values for [,].

Answer 5

replace your arrays with a class:

class MyArray {
    private MyMapType[] myArray = new myMapType[size]
    MyMapType this[index] {
       get{return myArray[index + offset];}
    }

}

you can set the size and the offset in the constructor or even change it at will.

Building on this example here is another version:

class MyArray {
    private MyMapType[] positives = new myMapType[size]
    private MyMapType[] negatives = new myMapType[size-1]
    MyMapType this[index] {
       get{return index >= 0 ? positives[index] : negateves[1-index];}
    }

}

It does not change the fact that you need to set the size for both of them. Honestly I like the first one better