How to split a number into individual digits in c#? [duplicate]

Question

I'd use modulus and a loop.

int[] GetIntArray(int num)
{
    List<int> listOfInts = new List<int>();
    while(num > 0)
    {
        listOfInts.Add(num % 10);
        num = num / 10;
    }
    listOfInts.Reverse();
    return listOfInts.ToArray();
}

Something like this will work, using Linq:

string result = "12345"
var intList = result.Select(digit => int.Parse(digit.ToString()));

This will give you an IEnumerable list of ints.

If you want an IEnumerable of strings:

var intList = result.Select(digit => digit.ToString());

or if you want a List of strings:

var intList = result.ToList();

Well, a string is an IEnumerable and also implements an indexer, so you can iterate through it or reference each character in the string by index.

The fastest way to get what you want is probably the ToCharArray() method of a String:

var myString = "12345";

var charArray = myString.ToCharArray(); //{'1','2','3','4','5'}

You can then convert each Char to a string, or parse them into bytes or integers. Here's a Linq-y way to do that:

byte[] byteArray = myString.ToCharArray().Select(c=>byte.Parse(c.ToString())).ToArray();

A little more performant if you're using ASCII/Unicode strings:

byte[] byteArray = myString.ToCharArray().Select(c=>(byte)c - 30).ToArray();

That code will only work if you're SURE that each element is a number; otherisw the parsing will throw an exception. A simple Regex that will verify this is true is "^\d+$" (matches a full string consisting of one or more digit characters), used in the Regex.IsMatch() static method.

You can simply do:

"123456".Select(q => new string(q,1)).ToArray();

to have an enumerable of integers, as per comment request, you can:

"123456".Select(q => int.Parse(new string(q,1))).ToArray();

It is a little weak since it assumes the string actually contains numbers.

Here is some code that might help you out. Strings can be treated as an array of characters

string numbers = "12345";
int[] intArray = new int[numbers.Length];
for (int i=0; i < numbers.Length; i++)
{
   intArray[i] = int.Parse(numbers[i]);
}