Double to string conversion without scientific notation

I have just improvised on the code above to make it work for negative exponential values.

using System;
using System.Text.RegularExpressions;
using System.IO;
using System.Text;
using System.Threading;

namespace ConvertNumbersInScientificNotationToPlainNumbers
{
    class Program
    {
        private static string ToLongString(double input)
        {
            string str = input.ToString(System.Globalization.CultureInfo.InvariantCulture);

            // if string representation was collapsed from scientific notation, just return it:
            if (!str.Contains("E")) return str;

            var positive = true;
            if (input < 0)
            {
                positive = false;
            }

            string sep = Thread.CurrentThread.CurrentCulture.NumberFormat.NumberDecimalSeparator;
            char decSeparator = sep.ToCharArray()[0];

            string[] exponentParts = str.Split('E');
            string[] decimalParts = exponentParts[0].Split(decSeparator);

            // fix missing decimal point:
            if (decimalParts.Length == 1) decimalParts = new string[] { exponentParts[0], "0" };

            int exponentValue = int.Parse(exponentParts[1]);

            string newNumber = decimalParts[0].Replace("-", "").
                Replace("+", "") + decimalParts[1];

            string result;

            if (exponentValue > 0)
            {
                if (positive)
                    result =
                        newNumber +
                        GetZeros(exponentValue - decimalParts[1].Length);
                else

                    result = "-" +
                     newNumber +
                     GetZeros(exponentValue - decimalParts[1].Length);


            }
            else // negative exponent
            {
                if (positive)
                    result =
                        "0" +
                        decSeparator +
                        GetZeros(exponentValue + decimalParts[0].Replace("-", "").
                                   Replace("+", "").Length) + newNumber;
                else
                    result =
                    "-0" +
                    decSeparator +
                    GetZeros(exponentValue + decimalParts[0].Replace("-", "").
                             Replace("+", "").Length) + newNumber;

                result = result.TrimEnd('0');
            }
            float temp = 0.00F;

            if (float.TryParse(result, out temp))
            {
                return result;
            }
            throw new Exception();
        }

        private static string GetZeros(int zeroCount)
        {
            if (zeroCount < 0)
                zeroCount = Math.Abs(zeroCount);

            StringBuilder sb = new StringBuilder();

            for (int i = 0; i < zeroCount; i++) sb.Append("0");

            return sb.ToString();
        }

        public static void Main(string[] args)
        {
            //Get Input Directory.
            Console.WriteLine(@"Enter the Input Directory");
            var readLine = Console.ReadLine();
            if (readLine == null)
            {
                Console.WriteLine(@"Enter the input path properly.");
                return;
            }
            var pathToInputDirectory = readLine.Trim();

            //Get Output Directory.
            Console.WriteLine(@"Enter the Output Directory");
            readLine = Console.ReadLine();
            if (readLine == null)
            {
                Console.WriteLine(@"Enter the output path properly.");
                return;
            }
            var pathToOutputDirectory = readLine.Trim();

            //Get Delimiter.
            Console.WriteLine("Enter the delimiter;");
            var columnDelimiter = (char)Console.Read();

            //Loop over all files in the directory.
            foreach (var inputFileName in Directory.GetFiles(pathToInputDirectory))
            {
                var outputFileWithouthNumbersInScientificNotation = string.Empty;
                Console.WriteLine("Started operation on File : " + inputFileName);

                if (File.Exists(inputFileName))
                {
                    // Read the file
                    using (var file = new StreamReader(inputFileName))
                    {
                        string line;
                        while ((line = file.ReadLine()) != null)
                        {
                            String[] columns = line.Split(columnDelimiter);
                            var duplicateLine = string.Empty;
                            int lengthOfColumns = columns.Length;
                            int counter = 1;
                            foreach (var column in columns)
                            {
                                var columnDuplicate = column;
                                try
                                {
                                    if (Regex.IsMatch(columnDuplicate.Trim(),
                                                      @"^[+-]?[0-9]+(\.[0-9]+)?[E]([+-]?[0-9]+)$",
                                                      RegexOptions.IgnoreCase))
                                    {
                                        Console.WriteLine("Regular expression matched for this :" + column);

                                        columnDuplicate = ToLongString(Double.Parse
                                                                           (column,
                                                                            System.Globalization.NumberStyles.Float));

                                        Console.WriteLine("Converted this no in scientific notation " +
                                                          "" + column + "  to this number " +
                                                          columnDuplicate);
                                    }
                                }
                                catch (Exception)
                                {

                                }
                                duplicateLine = duplicateLine + columnDuplicate;

                                if (counter != lengthOfColumns)
                                {
                                    duplicateLine = duplicateLine + columnDelimiter.ToString();
                                }
                                counter++;
                            }
                            duplicateLine = duplicateLine + Environment.NewLine;
                            outputFileWithouthNumbersInScientificNotation = outputFileWithouthNumbersInScientificNotation + duplicateLine;
                        }

                        file.Close();
                    }

                    var outputFilePathWithoutNumbersInScientificNotation
                        = Path.Combine(pathToOutputDirectory, Path.GetFileName(inputFileName));

                    //Create Directory If it does not exist.
                    if (!Directory.Exists(pathToOutputDirectory))
                        Directory.CreateDirectory(pathToOutputDirectory);

                    using (var outputFile =
                        new StreamWriter(outputFilePathWithoutNumbersInScientificNotation))
                    {
                        outputFile.Write(outputFileWithouthNumbersInScientificNotation);
                        outputFile.Close();
                    }

                    Console.WriteLine("The transformed file is here :" +
                        outputFilePathWithoutNumbersInScientificNotation);
                }
            }
        }
    }
}

This code takes an input directory and based on the delimiter converts all values in scientific notation to numeric format.

Thanks

I don't know if my answer to the question can still be helpful. But in this case I suggest the "decomposition of the double variable into decimal places" to store it in an Array / Array of data of type String.

This process of decomposition and storage in parts (number by number) from double to string, would basically work with the use of two loops and an "alternative" (if you thought of workaround, I think you got it), where the first loop will extract the values from double without converting to String, resulting in blessed scientific notation and storing number by number in an Array. And this will be done using MOD - the same method to check a palindrome number, which would be for example:

String[] Array_ = new double[ **here you will put an extreme value of places your DOUBLE can reach, you must have a prediction**];

for (int i = 0, variableDoubleMonstrous > 0, i++){
x = variableDoubleMonstrous %10;
Array_[i] = x;
variableDoubleMonstrous /= 10;
}

And the second loop to invert the Array values ​​(because in this process of checking a palindrome, the values ​​invert from the last place, to the first, from the penultimate to the second and so on. Remember?) to get the original value:

String[] ArrayFinal = new String[the same number of "places" / indices of the other Array / Data array];

int lengthArray = Array_.Length;

for (int i = 0, i < Array_.Length, i++){
    FinalArray[i] = Array_[lengthArray - 1];
    lengthArray--;
    }

***Warning: There's a catch that I didn't pay attention to. In that case there will be no "." (floating point decimal separator or double), so this solution is not generalized. But if it is really important to use decimal separators, unfortunately the only possibility (If done well, it will have a great performance) is: **Use a routine to get the position of the decimal point of the original value, the one with scientific notation - the important thing is that you know that this floating point is before a number such as the "Length" position x, and after a number such as the y position - extracting each digit using the loops - as shown above - and at the end "export" the data from the last Array to another one, including the decimal place divider (the comma, or the period , if variable decimal, double or float) in the imaginary position that was in the original variable, in the "real" position of that matrix.

*** The concept of position is, find out how many numbers occur before the decimal point, so with this information you will be able to store in the String Array the point in the real position.

NEEDS THAT CAN BE MADE:

But then you ask:

• But what about when I'm going to convert String to a floating point value? My answer is that you use the second matrix of this entire process (the one that receives the inversion of the first matrix that obtains the numbers by the palindrome method) and use it for the conversion, but always making sure, when necessary, of the position of the decimal place in future situations, in case this conversion (Double -> String) is needed again.

But what if the problem is to use the value of the converted Double (Array of Strings) in a calculation. Then in this case you went around in circles. Well, the original variable will work anyway even with scientific notation. The only difference between floating point and decimal variable types is in the rounding of values, which depending on the purpose, it will only be necessary to change the type of data used, but it is dangerous to have a significant loss of information, look here