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

Say I have 12345.

I'd like individual items for each number. A String would do or even an individual number.

Does the .Split method have an overload for this?

Solution 1:

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();
}

Solution 2:

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();

Solution 3:

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.