Converting a string number into sequence of digits - .Net 2.0

Question

Given a string

string result = "01234"

I want to get the separate integers 0,1,2,3,4 from the string.

How to do that?

1

The following code is giving me the ascii values

List<int> ints = new List<int>();

    foreach (char c in result.ToCharArray())
    {
        ints.Add(Convert.ToInt32(c));
    }

Answer 1

        List<int> ints = new List<int>();

        foreach (char c in result.ToCharArray())
        {
            ints.Add(Convert.ToInt32(c));
        }

Answer 2

string result = "01234";
List<int> list = new List<int>();
foreach (var item in result)
{
    list.Add(item - '0');
}

Answer 3

Index into the string to extract each character. Convert each character into a number. Code left as an exercise for the reader.

Answer 4

You could use LINQ:

var ints = result.Select(c => Int32.Parse(c.ToString()));

Edit: Not using LINQ, your loop seems good enough. Just use Int32.Parse instead of Convert.ToInt32:

List<int> ints = new List<int>();

foreach (char c in result.ToCharArray())
{
    ints.Add(Int32.Parse(c.ToString()));
}

Answer 5

Loop the characters and convert each to a number. You can put them in an array:

int[] digits = result.Select(c => c - '0').ToArray();

Or you can loop through them directly:

foreach (int digit in result.Select(c => c - '0')) {
   ...
}

Edit:
As you clarified that you are using framework 2.0, you can apply the same calculation in your loop:

List<int> ints = new List<int>(result.Length);

foreach (char c in result) {
    ints.Add(c - '0');
}

Note: Specify the capacity when you create the list, that elliminates the need for the list to resize itself. You don't need to use ToCharArray to loop the characters in the string.

Answer 6

EDIT: I hadn't spotted the ".NET 2.0" requirement. If you're going to do a lot of this sort of thing, it would probably be worth using LINQBridge, and see the later bit - particularly if you can use C# 3.0 while still targeting 2.0. Otherwise:

List<int> integers = new List<int>(text.Length);
foreach (char c in text)
{
    integers.Add(c - '0');
}

Not as neat, but it will work. Alternatively:

List<char> chars = new List<char>(text);
List<int> integers = chars.ConvertAll(delegate(char c) { return c - '0'; });

Or if you'd be happy with an array:

char[] chars = text.ToCharArray();
int[] integers = Arrays.ConvertAll<char, int>(chars, 
                            delegate(char c) { return c - '0'; });

---

Original answer

Some others have suggested using ToCharArray. You don't need to do that - string already implements IEnumerable<char>, so you can already treat it as a sequence of characters. You then just need to turn each character digit into the integer representation; the easiest way of doing that is to subtract the Unicode value for character '0':

IEnumerable<int> digits = text.Select(x => x - '0');

If you want this in a List<int> instead, just do:

List<int> digits = text.Select(x => x - '0').ToList();

Answer 7

    static int[] ParseInts(string s) {
        int[] ret = new int[s.Length];
        for (int i = 0; i < s.Length; i++) {
            if (!int.TryParse(s[i].ToString(), out ret[i]))
                throw new InvalidCastException(String.Format("Cannot parse '{0}' as int (char {1} of {2}).", s[i], i, s.Length));
        }
        return ret;
    }

Answer 8

another solution...

string numbers = "012345";
List<int> list = new List<int>();

foreach (char c in numbers)
{
    list.Add(int.Parse(c.ToString()));
}

no real need to do a char array from the string since a string can be enumerated over just like an array.

also, the ToString() makes it a string so the int.Parse will give you the number instead of the ASCII value you get when converting a char.