Integer to Integer Array C#

Question

I had to split an int \"123456\" each value of it to an Int[] and i have already a Solution but i dont know is there any better way : My solution was :

publi         


        

Answer 1

string DecimalToBase(int iDec, int numbase)
        {
            string strBin = "";
            int[] result = new int[32];
            int MaxBit = 32;
            for(; iDec > 0; iDec/=numbase)
            {
                int rem = iDec % numbase;
                    result[--MaxBit] = rem;
            } 
            for (int i=0;i<result.Length;i++)
                if ((int)result.GetValue(i) >= base10)
                    strBin += cHexa[(int)result.GetValue(i)%base10];
                else
                    strBin += result.GetValue(i);
            strBin = strBin.TrimStart(new char[] {'0'});
            return strBin;
        }
        int BaseToDecimal(string sBase, int numbase)
        {
            int dec = 0;
            int b;
            int iProduct=1;
            string sHexa = "";
            if (numbase > base10)
                for (int i=0;i<cHexa.Length;i++)
                    sHexa += cHexa.GetValue(i).ToString();
            for(int i=sBase.Length-1; i>=0; i--,iProduct *= numbase)
            {
                string sValue = sBase[i].ToString();
                if (sValue.IndexOfAny(cHexa) >=0)
                    b=iHexaNumeric[sHexa.IndexOf(sBase[i])];
                else 
                    b= (int) sBase[i] - asciiDiff;
                dec += (b * iProduct);
            } 
            return dec; 
        }

Answer 2

Here is a Good Solution for Convert Your Integer into Array i.e: int a= 5478 into int[] There is no issue if You Have a String and You want to convert a String into integer Array for example string str=4561; //Convert into
array[0]=4;
array[1]=5;
array[2]=6;
array[3]=7;

Note: The Number of zero (0) in devider are Equal to the Length of input and Set Your Array Length According to Your input length
Now Check the Coding:

         string str=4587;
            int value = Convert.ToInt32(str);
            int[] arr = new int[4];
            int devider = 10000;
            for (int i = 0; i < str.Length; i++)
            {
                int m = 0;
                devider /= 10;
                arr[i] = value / devider;
                m = value / devider;
                value -= (m * devider);
            }

Answer 3

int[] outarry = Array.ConvertAll(num.ToString().ToArray(), x=>(int)x);

but if you want to convert it to 1,2,3,4,5:

int[] outarry = Array.ConvertAll(num.ToString().ToArray(), x=>(int)x - 48);

Answer 4

You can do that without converting it to a string and back:

public static int[] intToArray(int num) {
  List<int> numbers = new List<int>();
  do {
    numbers.Insert(0, num % 10);
    num /= 10;
  } while (num > 0);
  return numbers.ToArray();
}

It only works for positive values, of course, but your original code also have that limitation.

Answer 5

i had similar requirement .. i took from many good ideas, and added a couple missing pieces .. where many folks weren’t handling zero or negative values. this is what i came up with:

    public static int[] DigitsFromInteger(int n)
    {
        int _n = Math.Abs(n);
        int length = ((int)Math.Log10(_n > 0 ? _n : 1)) + 1;
        int[] digits = new int[length];
        for (int i = 0; i < length; i++)
        {
            digits[(length - i) - 1] = _n % 10 * ((i == (length - 1) && n < 0) ? -1 : 1);
            _n /= 10;
        }
        return digits;
    }

i think this is pretty clean .. although, it is true we're doing a conditional check and several extraneous calculations with each iteration .. while i think they’re nominal in this case, you could optimize a step further this way:

    public static int[] DigitsFromInteger(int n)
    {
        int _n = Math.Abs(n);
        int length = ((int)Math.Log10(_n > 0 ? _n : 1)) + 1;
        int[] digits = new int[length];
        for (int i = 0; i < length; i++)
        {
            //digits[(length - i) - 1] = _n % 10 * ((i == (length - 1) && n < 0) ? -1 : 1);
            digits[(length - i) - 1] = _n % 10;
            _n /= 10;
        }
        if (n < 0)
            digits[0] *= -1;
        return digits;
    }

Answer 6

I believe this will be better than converting back and forth. As opposed to JBSnorro´s answer I reverse after converting to an array and therefore avoid IEnumerable´s which I think will contribute to a little bit faster code. This method work for non negative numbers, so 0 will return new int[1] { 0 }.

If it should work for negative numbers, you could do a n = Math.Abs(n) but I don't think that makes sense.

Furthermore, if it should be more performant, I could create the final array to begin with by making a binary-search like combination of if-statements to determine the number of digits.

public static int[] digitArr(int n)
{
    if (n == 0) return new int[1] { 0 };

    var digits = new List<int>();

    for (; n != 0; n /= 10)
        digits.Add(n % 10);

    var arr = digits.ToArray();
    Array.Reverse(arr);
    return arr;
}

Update 2018:

public static int numDigits(int n) {
    if (n < 0) {
        n = (n == Int32.MinValue) ? Int32.MaxValue : -n;
    }
    if (n < 10) return 1;
    if (n < 100) return 2;
    if (n < 1000) return 3;
    if (n < 10000) return 4;
    if (n < 100000) return 5;
    if (n < 1000000) return 6;
    if (n < 10000000) return 7;
    if (n < 100000000) return 8;
    if (n < 1000000000) return 9;
    return 10;
}

public static int[] digitArr2(int n)
{
    var result = new int[numDigits(n)];
    for (int i = result.Length - 1; i >= 0; i--) {
        result[i] = n % 10;
        n /= 10;
    }
    return result;
}