I have a array need to handles values that are not null

var arr = [null,2,null,5,4];
var _arr = RemoveNull(arr); // [2,5,4]
var _arr2 = Encrypt(_arr); // [e1,e2,e3]
var arr2 = Tansform(_arr2); //[null,e1,null,e2,e3]

What should I do to get arr2 from arr?

CodePudding user response：

In Encrypt method, you can ignore null. What exactly is the array data type?

public static void Main()
    {
        int?[] Arr = new int?[] { null,2,null,5,4 };
        string[] OutArr = SkipNullAndEncrypt(Arr);
        foreach(string Item in OutArr)
        {
            Console.Write(Item   " ");
        }
        //Output: null e2 null e5 e4
    }
    
    private static string[] SkipNullAndEncrypt(int?[] InArr)
    {
        int Len = InArr.Length;
        string[] OutArr = new string[Len];
        int i = 0;
        foreach(int? ThisItem in InArr)
        {
            if(ThisItem.HasValue)
            {
                //Encrypt call here. I have just concatenated.
                OutArr[i] = "e"   ThisItem.Value.ToString();
            }
            else
            {
                OutArr[i] = "null"; // Only to make it visible in the output
            }
            i  ;
        }
        return OutArr;
    }

From you comment, this is how you can do it:

using System;
using System.Collections.Generic;
using System.Linq;
                    
public class Program
{
    public static void Main()
    {
        string[] Arr = new string[] { null, "2", null, "5", "4" };
        string[] ArrNullRemoved = RemoveNull(Arr);
        DisplayArr(ArrNullRemoved); //2 5 4
        string[] EncArr = EncryptArr(ArrNullRemoved);
        DisplayArr(EncArr);//e2 e5 e4
        string[] FinArr = TransformArr(EncArr, Arr);
        DisplayArr(FinArr);//null e2 null e5 e4 
    }
    
    private static string[] TransformArr(string[] EncArr, string[] OgArr)
    {
        string[] OutArr = new string[OgArr.Length];
        int i = 0;
        int E_Pointer = 0;
        foreach(string Item in OgArr)
        {
            if(string.IsNullOrWhiteSpace(Item))
            {
                OutArr[i] = "null"; //Only for display
            }
            else
            {
                OutArr[i] = EncArr[E_Pointer];
                E_Pointer  ;
            }
            i  ;
        }
        return OutArr;
    }
    
    private static string[] RemoveNull(string[] InArr)
    {
        return InArr.Where(a => !string.IsNullOrWhiteSpace(a)).ToArray();
    }
    
    private static void DisplayArr(string[] InArr)
    {
        foreach(string Item in InArr)
        {
            Console.Write(Item   " ");
        }
        Console.WriteLine();
    }
    
    private static string[] EncryptArr(string[] InArr)
    {
        int i = 0;
        foreach(string Item in InArr)
        {
            InArr[i] = "e"   Item;
            i  ;
        }
        return InArr;
    }
}

CodePudding user response：

string[] arr  = new string[5] { null, "b", "c", null, "e" };
        var _arr = RemoveNull(arr );
        var _arr2  = Encrypt(_arr);
        List<string> temp = new();
        int j = 0;
        for (int i = 0; i < arr .Length; i  )
        {
            if (arr [i] == null)
                temp.Add(null);
            else
            {
                temp.Add(_arr2 [j]);
                j  ;
            }
        }
        var arr2 = temp.ToArray();

Input { null, "b", "c", null, "e" } output [ null, "eb", "ec", null, "ee" ]