按名称访问唯一数组

Question

我有一组像这样的整数数组-

public int[] box1 = {1, 0, 2};
public int[] box2 = {3, 1, 0};
public int[] box3 = {2, 3, 1};

我需要做的是通过唯一的数组名称动态访问它们，并从中返回一个随机元素，使用类似这样的东西-

foo="box"+2[random int];

其中 foo 是我的临时字符串，包括“box”前缀，将我想要的数字添加到“box”，并从“box2”中获取一个随机元素。 （例如：foo=3）

如果我通过字符串方法执行此操作，它会创建正确的命名法，但它只是一个字符串，我不能使用它在脚本中实际访问这些作为实际的类/数组元素并将它们传递给其他东西。

我该怎么做呢？阅读手册几个小时，尝试了列表，但我认为我做的不对。谢谢！

Answer 1

只需分解您真正想做的事情，您就会发现它是多么容易。就像我在评论部分提到的Dictionary 一样，您仍然需要另外两个 C# 功能来完成确切的语法。

你希望能够做到这一点：

foo="box"+2[random int];

与此相同：

int valueFromArray  = arrayVariableName [index];

---

在下面的示例中，我们可以假设 MyScript 是我们脚本的名称。

1。你需要一个可以保存名字和int数组的字典。

Dictionary<string, int[]> boxes

2。您需要一种将 "box"+2 或 arrayVariableName 转换为当前脚本实例的方法。这可以通过 C# 中的隐式转换运算符功能来完成。您可以将 "box"+2 或 arrayVariableName 传递到这个隐式 MyScript 中，然后将其存储到全局变量中以供下一步使用。

//The global variable that holds the arrayVariableName to access
static string targetBox = null;

//Implicit conversion operators (box array name to this script(MyScript) instance)
public static implicit operator MyScript(string box)
{
    return setTargetAndGetInstance(box);
}

public static MyScript setTargetAndGetInstance(string box)
{
    if (instance.boxes.ContainsKey(box))
    {
        //Set the box requested. This will be needed in the Indexer overloading above
        targetBox = box;
        return instance;
    }
    else
        return null;
}

3。现在，您可以实现 [index] 语法。这可以通过索引器重载功能来实现。

//Indexer overloading (index to int (value in array))
public int this[int index]
{
    get
    {
        //Get value based on value set in the implicit operators
        return accessBox(targetBox, index);
    }
}

现在，当你这样做时，"box"+2，它将在 implicit 转换运算符的帮助下返回 this(MyScript) 的实例。然后它将允许您使用索引器重载功能执行 [random int]。

---

下面的代码是您问题中的语法示例以及执行此操作的其他类似方法。 ^{包括类似的，因为它们看起来比您要求的更好}：

用一个简单的功能：

int test1 = accessBox("box" + 2, UnityEngine.Random.Range(0, 3));
Debug.Log(test1);

使用arrayVariableName [index] 语法：

^{你正在寻找这个，但 MyScript 的转换看起来很糟糕}

int test2 = ((MyScript)("box" + 2))[UnityEngine.Random.Range(0, 3)];
Debug.Log(test2);

使用[arrayVariableName][index] 语法：

int test3 = this["box" + 2][UnityEngine.Random.Range(0, 3)];
Debug.Log(test3);

使用[arrayVariableName, index] 语法

int test4 = this["box" + 2, UnityEngine.Random.Range(0, 3)];
Debug.Log(test4);

完整的功能示例：

using System.Collections.Generic;
using UnityEngine;

public class MyScript : MonoBehaviour
{

    public int[] box1 = { 1, 0, 2 };
    public int[] box2 = { 3, 1, 0 };
    public int[] box3 = { 2, 3, 1 };


    public Dictionary<string, int[]> boxes = new Dictionary<string, int[]>();
    private static MyScript instance;

    void Awake()
    {
        instance = this;

        //Add to Dictionary
        addBox();

        int test1 = accessBox("box" + 2, UnityEngine.Random.Range(0, 3));
        Debug.Log(test1);

        int test2 = ((MyScript)("box" + 2))[UnityEngine.Random.Range(0, 3)];
        Debug.Log(test2);

        int test3 = this["box" + 2][UnityEngine.Random.Range(0, 3)];
        Debug.Log(test3);

        int test4 = this["box" + 2, UnityEngine.Random.Range(0, 3)];
        Debug.Log(test4);
    }

    void addBox()
    {
        boxes.Add("box1", box1);
        boxes.Add("box2", box2);
        boxes.Add("box3", box3);
    }

    public int accessBox(string box, int index)
    {
        //Return the array from the Dictionary
        int[] tempVar;
        if (boxes.TryGetValue(box, out tempVar))
        {
            //Return the spicified index
            return tempVar[index];
        }
        else
        {
            //ERROR - return -1
            return -1;
        }
    }


    //Indexer overloading (index to int (value in array))
    public int this[int index]
    {
        get
        {
            //Get value based on value set in the implicit operators
            return accessBox(targetBox, index);
        }
    }

    static string targetBox = null;

    //Implicit conversion operators (box array name to this script(MyScript) instance)
    public static implicit operator MyScript(string box)
    {
        return setTargetAndGetInstance(box);
    }

    public static MyScript setTargetAndGetInstance(string box)
    {
        if (instance.boxes.ContainsKey(box))
        {
            //Set the box requested. This will be needed in the Indexer overloading above
            targetBox = box;
            return instance;
        }
        else
            return null;
    }

    //Indexer overloading (box array name to this script(MyScript) instance)
    public MyScript this[string box]
    {
        get
        {
            return setTargetAndGetInstance(box);
        }
    }

    //Indexer overloading (box array name to int)
    public int this[string box, int index]
    {
        get
        {
            setTargetAndGetInstance(box);
            return accessBox(box, index);
        }
    }
}

Answer 2

这是您的问题的通用解决方案，使用 Dictionary<TKey,TValue>：

主要代码：

using System;
using System.Collections.Generic;

public class Class1
{
    public void Example()
    {
        // a dictionary with string keys

        var string1 = "abcd";
        var string2 = "efgh";

        var dictionary1 = new Dictionary<string, int[]>
        {
            {string1, new[] {0, 1, 2}},
            {string2, new[] {3, 4, 5}}
        };


        // a dictionary with custom type

        var box1 = new Box(10, 10);
        var box2 = new Box(20, 20);

        var dictionary2 = new Dictionary<Box, int[]>
        {
            {box1, new[] {0, 1, 2}},
            {box2, new[] {3, 4, 5}}
        };

        // get random value from both dictionnaries

        var i1 = GetRandomInteger(dictionary1, string1);
        var i2 = GetRandomInteger(dictionary2, box1);
    }

    private int GetRandomInteger<TKey>(IDictionary<TKey, int[]> dictionary, TKey key)
    {
        if (!dictionary.ContainsKey(key))
            throw new KeyNotFoundException();

        var array = dictionary[key];

        // prefer UnityEngine.Random here since it's static 
        var index = new Random().Next(array.Length);

        var value = array[index];

        return value;
    }
}

额外代码：

public struct Box
{
    // a dictionary key should be immutable, therefore I use a struct
    // implement equality members so that when querying the dictionary,
    // it will find the value associated to the key
    // see https://docs.microsoft.com/en-us/dotnet/csharp/programming-guide/statements-expressions-operators/how-to-define-value-equality-for-a-type

    public int Width { get; }
    public int Height { get; }

    public Box(int width, int height)
    {
        Width = width;
        Height = height;
    }

    public bool Equals(Box other)
    {
        return Width == other.Width && Height == other.Height;
    }

    public override bool Equals(object obj)
    {
        if (ReferenceEquals(null, obj))
            return false;
        return obj is Box && Equals((Box) obj);
    }

    public override int GetHashCode()
    {
        unchecked
        {
            return (Width * 397) ^ Height;
        }
    }

    public static bool operator ==(Box left, Box right)
    {
        return left.Equals(right);
    }

    public static bool operator !=(Box left, Box right)
    {
        return !left.Equals(right);
    }
}