C# 不使用科学记数法的双精度到字符串转换
在.NET Framework中，如何在没有科学符号的情况下将double转换为浮点字符串表示形式 “小”样本（有效数量可以是任何大小，如C# 不使用科学记数法的双精度到字符串转换,c#,.net,floating-point,number-formatting,C#,.net,Floating Point,Number Formatting,在.NET Framework中，如何在没有科学符号的情况下将double转换为浮点字符串表示形式 “小”样本（有效数量可以是任何大小，如1.5E200或1e-200）： 没有一个是这样的，而且a似乎也不允许在十进制分隔符之后有一个开放的数字 这不是重复的，因为这里给出的答案不能解决眼前的问题。在这个问题上，公认的解决方案是使用一个固定点（例如20位），这不是我想要的。固定点格式化和修剪冗余0也不能解决问题，因为固定宽度的最大宽度为99个字符 注意：解决方案必须正确处理自定义数字格式（例如，其他
1.5E2001e-200编辑：问题实际上只是关于显示前面提到的数字。我知道浮点数是如何工作的，以及什么数字可以用它们来使用和计算。这是我到目前为止得到的，似乎是可行的，但也许有人有更好的解决方案：
private static readonly Regex rxScientific = new Regex(@"^(?<sign>-?)(?<head>\d+)(\.(?<tail>\d*?)0*)?E(?<exponent>[+\-]\d+)$", RegexOptions.IgnoreCase|RegexOptions.ExplicitCapture|RegexOptions.CultureInvariant);
public static string ToFloatingPointString(double value) {
return ToFloatingPointString(value, NumberFormatInfo.CurrentInfo);
}
public static string ToFloatingPointString(double value, NumberFormatInfo formatInfo) {
string result = value.ToString("r", NumberFormatInfo.InvariantInfo);
Match match = rxScientific.Match(result);
if (match.Success) {
Debug.WriteLine("Found scientific format: {0} => [{1}] [{2}] [{3}] [{4}]", result, match.Groups["sign"], match.Groups["head"], match.Groups["tail"], match.Groups["exponent"]);
int exponent = int.Parse(match.Groups["exponent"].Value, NumberStyles.Integer, NumberFormatInfo.InvariantInfo);
StringBuilder builder = new StringBuilder(result.Length+Math.Abs(exponent));
builder.Append(match.Groups["sign"].Value);
if (exponent >= 0) {
builder.Append(match.Groups["head"].Value);
string tail = match.Groups["tail"].Value;
if (exponent < tail.Length) {
builder.Append(tail, 0, exponent);
builder.Append(formatInfo.NumberDecimalSeparator);
builder.Append(tail, exponent, tail.Length-exponent);
} else {
builder.Append(tail);
builder.Append('0', exponent-tail.Length);
}
} else {
builder.Append('0');
builder.Append(formatInfo.NumberDecimalSeparator);
builder.Append('0', (-exponent)-1);
builder.Append(match.Groups["head"].Value);
builder.Append(match.Groups["tail"].Value);
}
result = builder.ToString();
}
return result;
}
// test code
double x = 1.0;
for (int i = 0; i < 200; i++) {
x /= 10;
}
Console.WriteLine(x);
Console.WriteLine(ToFloatingPointString(x));
private static readonly Regex rxScientific=new Regex（@“^（？-？）（？\d+）（\.（？\d*）0*）？E（？[+\-]\d+）$”，RegexOptions.IgnoreCase | RegexOptions.ExplicitCapture | RegexOptions.CultureInvariant）；
公共静态字符串ToFloatingPointString（双值）{
返回ToFloatingPointString（值，NumberFormatInfo.CurrentInfo）；
}
公共静态字符串ToFloatingPointString（双值，NumberFormatInfo formatInfo）{
字符串结果=value.ToString（“r”，NumberFormatInfo.InvariantInfo）；
Match Match=rxScientific.Match（结果）；
如果（匹配成功）{
Debug.WriteLine（“找到的科学格式：{0}=>[{1}][{2}][{3}][{4}]”，结果，匹配.Groups[“sign”]、匹配.Groups[“head”]、匹配.Groups[“tail”]、匹配.Groups[“index”]；
int exponent=int.Parse（match.Groups[“exponent”].Value，NumberStyles.Integer，NumberFormatInfo.InvariantInfo）；
StringBuilder=newStringBuilder（result.Length+Math.Abs（exponent））；
builder.Append（match.Groups[“sign”].Value）；
如果（指数>=0）{
builder.Append（match.Groups[“head”].Value）；
字符串tail=match.Groups[“tail”].Value；
if（指数<尾部长度）{
追加（尾部，0，指数）；
builder.Append（formatInfo.NumberDecimalSeparator）；
追加（尾部、指数、尾部、长度指数）；
}否则{
附加（尾部）；
builder.Append（'0'，指数尾.Length）；
}
}否则{
builder.Append（'0'）；
builder.Append（formatInfo.NumberDecimalSeparator）；
builder.Append（'0'，（-指数）-1）；
builder.Append（match.Groups[“head”].Value）；
builder.Append（match.Groups[“tail”].Value）；
}
结果=builder.ToString（）；
}
返回结果；
}
//测试代码
双x=1.0；
对于（int i=0；i<200；i++）{
x/=10；
}
控制台写入线（x）；
Console.WriteLine（ToFloatingPointString（x））；
data.ToString("n");
根据jcasso所说的，你可以做的是通过改变指数来调整你的双精度值，这样你最喜欢的格式就可以为你做，应用格式，然后用零填充结果以补偿调整。在过去，当我们不得不编写自己的格式化程序时，我们将分离尾数和指数，并分别格式化它们
在Jon Skeet（）的这篇文章中，他提供了一个指向DoubleConverter.cs例程的链接，该例程应该完全满足您的需要。Skeet在强制性的基于对数的解决方案中也提到了这一点。请注意，这个解决方案，因为它涉及做数学，可能会降低您的数字精度一点。没有经过严格的测试
private static string DoubleToLongString(double x)
{
int shift = (int)Math.Log10(x);
if (Math.Abs(shift) <= 2)
{
return x.ToString();
}
if (shift < 0)
{
double y = x * Math.Pow(10, -shift);
return "0.".PadRight(-shift + 2, '0') + y.ToString().Substring(2);
}
else
{
double y = x * Math.Pow(10, 2 - shift);
return y + "".PadRight(shift - 2, '0');
}
}
private静态字符串DoubleToLongString（双x）
{
int shift=（int）Math.Log10（x）；
如果（Math.Abs（shift）试试这个：
public static string DoubleToFullString(double value,
NumberFormatInfo formatInfo)
{
string[] valueExpSplit;
string result, decimalSeparator;
int indexOfDecimalSeparator, exp;
valueExpSplit = value.ToString("r", formatInfo)
.ToUpper()
.Split(new char[] { 'E' });
if (valueExpSplit.Length > 1)
{
result = valueExpSplit[0];
exp = int.Parse(valueExpSplit[1]);
decimalSeparator = formatInfo.NumberDecimalSeparator;
if ((indexOfDecimalSeparator
= valueExpSplit[0].IndexOf(decimalSeparator)) > -1)
{
exp -= (result.Length - indexOfDecimalSeparator - 1);
result = result.Replace(decimalSeparator, "");
}
if (exp >= 0) result += new string('0', Math.Abs(exp));
else
{
exp = Math.Abs(exp);
if (exp >= result.Length)
{
result = "0." + new string('0', exp - result.Length)
+ result;
}
else
{
result = result.Insert(result.Length - exp, decimalSeparator);
}
}
}
else result = valueExpSplit[0];
return result;
}
这是一种字符串解析解决方案，将源代码（double）转换为字符串并解析为其组成部分。然后根据规则将其重新组合为完整的数字表示形式。它还根据请求考虑语言环境
更新：转换测试只包括一位数整数，这是标准值，但算法也适用于239483.340901e-20等
using System;
using System.Text;
using System.Globalization;
using System.Threading;
public class MyClass
{
public static void Main()
{
Console.WriteLine(ToLongString(1.23e-2));
Console.WriteLine(ToLongString(1.234e-5)); // 0.00010234
Console.WriteLine(ToLongString(1.2345E-10)); // 0.00000001002345
Console.WriteLine(ToLongString(1.23456E-20)); // 0.00000000000000000100023456
Console.WriteLine(ToLongString(5E-20));
Console.WriteLine("");
Console.WriteLine(ToLongString(1.23E+2)); // 123
Console.WriteLine(ToLongString(1.234e5)); // 1023400
Console.WriteLine(ToLongString(1.2345E10)); // 1002345000000
Console.WriteLine(ToLongString(-7.576E-05)); // -0.00007576
Console.WriteLine(ToLongString(1.23456e20));
Console.WriteLine(ToLongString(5e+20));
Console.WriteLine("");
Console.WriteLine(ToLongString(9.1093822E-31)); // mass of an electron
Console.WriteLine(ToLongString(5.9736e24)); // mass of the earth
Console.ReadLine();
}
private static string ToLongString(double input)
{
string strOrig = input.ToString();
string str = strOrig.ToUpper();
// if string representation was collapsed from scientific notation, just return it:
if (!str.Contains("E")) return strOrig;
bool negativeNumber = false;
if (str[0] == '-')
{
str = str.Remove(0, 1);
negativeNumber = true;
}
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] + decimalParts[1];
string result;
if (exponentValue > 0)
{
result =
newNumber +
GetZeros(exponentValue - decimalParts[1].Length);
}
else // negative exponent
{
result =
"0" +
decSeparator +
GetZeros(exponentValue + decimalParts[0].Length) +
newNumber;
result = result.TrimEnd('0');
}
if (negativeNumber)
result = "-" + result;
return result;
}
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();
}
}
使用系统；
使用系统文本；
利用制度全球化；
使用系统线程；
公共类MyClass
{
公共静态void Main（）
{
控制台写入线（ToLongString（1.23e-2））；
Console.WriteLine（ToLongString（1.234e-5））；//0.00010234
Console.WriteLine（ToLongString（1.2345E-10））；//0.00000001002345
Console.WriteLine（ToLongString（1.23456E-20））；//0.0000000000000000010023456
控制台写入线（ToLongString（5E-20））；
控制台。写线（“”）；
Console.WriteLine（ToLongString（1.23E+2））；//123
Console.WriteLine（ToLongString（1.234e5））；//1023400
Console.WriteLine（ToLongString（1.2345E10））；//100234.500000
控制台写入线（ToLongString（-7.576E-05））；//-0.00007576
Console.WriteLine（ToLongString（1.23456e20））；
控制台写入线（ToLongString（5e+20））；
控制台。写线（“”）；
Console.WriteLine（ToLongString（9.1093822E-31））；//电子的质量
Console.WriteLine（ToLongString（5.9736e24））；//地球的质量
Console.ReadLine（）；
}
专用静态字符串ToLongString（双输入）
{
string strOrig=input.ToString（）；
string str=strOrig.ToUpper（）；
//如果字符串表示从科学记数法中折叠，只需返回它：
using System;
using System.Text;
using System.Globalization;
using System.Threading;
public class MyClass
{
public static void Main()
{
Console.WriteLine(ToLongString(1.23e-2));
Console.WriteLine(ToLongString(1.234e-5)); // 0.00010234
Console.WriteLine(ToLongString(1.2345E-10)); // 0.00000001002345
Console.WriteLine(ToLongString(1.23456E-20)); // 0.00000000000000000100023456
Console.WriteLine(ToLongString(5E-20));
Console.WriteLine("");
Console.WriteLine(ToLongString(1.23E+2)); // 123
Console.WriteLine(ToLongString(1.234e5)); // 1023400
Console.WriteLine(ToLongString(1.2345E10)); // 1002345000000
Console.WriteLine(ToLongString(-7.576E-05)); // -0.00007576
Console.WriteLine(ToLongString(1.23456e20));
Console.WriteLine(ToLongString(5e+20));
Console.WriteLine("");
Console.WriteLine(ToLongString(9.1093822E-31)); // mass of an electron
Console.WriteLine(ToLongString(5.9736e24)); // mass of the earth
Console.ReadLine();
}
private static string ToLongString(double input)
{
string strOrig = input.ToString();
string str = strOrig.ToUpper();
// if string representation was collapsed from scientific notation, just return it:
if (!str.Contains("E")) return strOrig;
bool negativeNumber = false;
if (str[0] == '-')
{
str = str.Remove(0, 1);
negativeNumber = true;
}
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] + decimalParts[1];
string result;
if (exponentValue > 0)
{
result =
newNumber +
GetZeros(exponentValue - decimalParts[1].Length);
}
else // negative exponent
{
result =
"0" +
decSeparator +
GetZeros(exponentValue + decimalParts[0].Length) +
newNumber;
result = result.TrimEnd('0');
}
if (negativeNumber)
result = "-" + result;
return result;
}
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();
}
}
ToString(doubleVar, System.Globalization.NumberStyles.Number)
double d = double.MaxValue;
string s = d.ToString(d, System.Globalization.NumberStyles.Number);
doubleValue.ToString("F99").TrimEnd('0')
double d;
d = 1234.12341234;
d.ToString("#########0.#########");
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);
}
}
}
}
}
double number = 1.5E+200;
string s = number.ToString("#");
//Output: "150000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000"
public static class FormatStrings
{
public const string DoubleFixedPoint = "0.###################################################################################################################################################################################################################################################################################################################################################";
}
(0.000000005).ToString() // 5E-09
((decimal)(0.000000005)).ToString() // 0,000000005
string strdScaleFactor = dScaleFactor.ToString(); // where dScaleFactor = 3.531467E-05
decimal decimalScaleFactor = Decimal.Parse(strdScaleFactor, System.Globalization.NumberStyles.Float);
String t1 = (0.0001/7).ToString("0." + new string('#', 339)); // 0.0000142857142857143
String t2 = (0.0001/7).ToString("r"); // 1.4285714285714287E-05
public static class RoundTrip {
private static String[] zeros = new String[1000];
static RoundTrip() {
for (int i = 0; i < zeros.Length; i++) {
zeros[i] = new String('0', i);
}
}
private static String ToRoundTrip(double value) {
String str = value.ToString("r");
int x = str.IndexOf('E');
if (x < 0) return str;
int x1 = x + 1;
String exp = str.Substring(x1, str.Length - x1);
int e = int.Parse(exp);
String s = null;
int numDecimals = 0;
if (value < 0) {
int len = x - 3;
if (e >= 0) {
if (len > 0) {
s = str.Substring(0, 2) + str.Substring(3, len);
numDecimals = len;
}
else
s = str.Substring(0, 2);
}
else {
// remove the leading minus sign
if (len > 0) {
s = str.Substring(1, 1) + str.Substring(3, len);
numDecimals = len;
}
else
s = str.Substring(1, 1);
}
}
else {
int len = x - 2;
if (len > 0) {
s = str[0] + str.Substring(2, len);
numDecimals = len;
}
else
s = str[0].ToString();
}
if (e >= 0) {
e = e - numDecimals;
String z = (e < zeros.Length ? zeros[e] : new String('0', e));
s = s + z;
}
else {
e = (-e - 1);
String z = (e < zeros.Length ? zeros[e] : new String('0', e));
if (value < 0)
s = "-0." + z + s;
else
s = "0." + z + s;
}
return s;
}
private static void RoundTripUnitTest() {
StringBuilder sb33 = new StringBuilder();
double[] values = new [] { 123450000000000000.0, 1.0 / 7, 10000000000.0/7, 100000000000000000.0/7, 0.001/7, 0.0001/7, 100000000000000000.0, 0.00000000001,
1.23e-2, 1.234e-5, 1.2345E-10, 1.23456E-20, 5E-20, 1.23E+2, 1.234e5, 1.2345E10, -7.576E-05, 1.23456e20, 5e+20, 9.1093822E-31, 5.9736e24, double.Epsilon };
foreach (int sign in new [] { 1, -1 }) {
foreach (double val in values) {
double val2 = sign * val;
String s1 = val2.ToString("r");
String s2 = ToRoundTrip(val2);
double val2_ = double.Parse(s2);
double diff = Math.Abs(val2 - val2_);
if (diff != 0) {
throw new Exception("Value {0} did not pass ToRoundTrip.".Format2(val.ToString("r")));
}
sb33.AppendLine(s1);
sb33.AppendLine(s2);
sb33.AppendLine();
}
}
}
}