将数字字符串拆分为数字并发送到数组

Question

I want to split a 40 digit number and send each digit into an array called digits. ToArray doesn't work because it can't convert from char to int. Neither does Split I think? I'm stumped

edit: These are the instructions: Create a class HugeInteger which uses a 40-element array of digits to store integers as large as 40 digits each. Provide methods Input, ToString, Add and Subtract. For comparing HugeInteger objects, provide the following methods: IsEqualTo, IsNotEqualTo, IsGreaterThan, IsLessThan, IsGreaterThanOrEqualTo and IsLessThanOrEqualTo. Each of these is a method that returns true if the relationship holds between the two HugeInteger objects and returns false if the relationship does not hold. Provide method IsZero. In the Input method, use the string method ToCharArray to convert the input string into an array of characters, then iterate through these characters to create your HugeInteger.

Answer 1

string digits = "8957853759876839473454789595495735984339";
int[] array = digits.Select(x => (int)char.GetNumericValue(x)).ToArray();

Or

int[] array = digits.Select(x => x - 48).ToArray();

As @Haldo requested explanation about why this one should work, It is because char is implicitly castable to int. Live Demo

If you want to avoid getting Exception if there are characters that can not be parsed as numbers, you may ignore them:

int[] array = digits.Where(x => char.IsNumber(x)).Select(x => x - 48).ToArray();

Answer 2

You can use Select extension method to transform the characters into integers:

int[] result = str.Select(x => int.Parse(x.ToString()))
                  .ToArray();

or assuming there could be invalid characters:

int[] result = str.Where(char.IsDigit)
                  .Select(x => int.Parse(x.ToString()))
                  .ToArray();

Answer 3

To handle huge number the best way is to convert string of integers to an array of bytes. So code converts the decimal number to binary byte[] array. Is uses the method that is taught in school to do base conversion from decimal to hex using long division.

I tested code thoroughly by using every number between 0 and 2^24.

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace ConsoleApplication89
{
    class Program
    {
        static void Main(string[] args)
        {

            string digits = "8957853759876839473454789595495735984339";
            List<byte> results = Binary.GetBytes(digits);
            //test code
            //for (int i = 0; i < (Math.Pow(2,24)); i++)
            //{
            //    string digits = i.ToString();
            //    Console.WriteLine(i);
            //    List<byte> results = Binary.GetBytes(digits);
            //    long value = results.Select((x, j) => x << (j * 8)).Sum();
            //    if (i != value)
            //    {
            //        int a = 3;
            //    }
            //}
        }


    }
    public class Binary
    {
        public static List<byte> GetBytes(string input)
        {
            List<byte> results = new List<byte>();
            string divisorStr = input;


            int nibbleCount = 0;


            while (divisorStr.Length != 0)
            {
                int number = 0;
                string quotentStr = "";
                byte carry = 0;

                //divide a string by 16 to get remainders
                while (divisorStr.Length != 0)
                {
                    number = (carry * 10) + int.Parse(divisorStr.Substring(0, 1));
                    divisorStr = divisorStr.Substring(1);
                    if (divisorStr.Length == 0) exit = true;

                    int digit = number / 16;
                    if (quotentStr != "" | (digit != 0))
                    {
                        quotentStr += digit.ToString();
                    }
                    carry = (byte)(number % 16);
                }
                ///combine the remainders together into an array of bytes
                if (nibbleCount % 2 == 0)
                {
                    results.Add(carry);
                }
                else
                {
                    results[results.Count - 1] |= (byte)(carry << 4);
                }
                divisorStr = quotentStr;
                nibbleCount++;
            }
            return results;
        }
    }
}

Answer 4

Since you want it into just a char array, why not just call .ToString() on the int then call .ToCharArray() ?

 int nums = 123456789; char[] numss = nums.ToString().ToCharArray(); foreach(char n in numss) { Console.Write(string.Format("{0} ", n)); } // 1 2 3 4 5 6 7 8 9... 

Since I misread the question and everybody is using the Select extension, why not just use a simple for loop and convert them to int .

string nums = "12345";
int [] digits = new int[nums.Length];

for(int i = 0; i < nums.Length; i++) {
    digits[i] = Convert.ToInt32(Char.GetNumericValue(nums[i]));
}

foreach(int n in digits) {
    Console.Write(string.Format("{0} ", n));
}
// 1 2 3 4 5