在C#中将字符串转换为double
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Converting string to double in C#
提问by whoah
I have a long string with double-type values separated by #-value1#value2#value3#etc
我有一个用#-value1#value2#value3#等分隔的双类型值的长字符串
I splitted it to string table. Then, I want to convert every single element from this table to double type and I get an error. What is wrong with type-conversion here?
我将它拆分为字符串表。然后，我想将此表中的每个元素都转换为双精度类型，但出现错误。这里的类型转换有什么问题？
string a = "52.8725945#18.69872650000002#50.9028073#14.971600200000012#51.260062#15.5859949000000662452.23862099999999#19.372202799999250800000045#51.7808372#19.474096499999973#";
string[] someArray = a.Split(new char[] { '#' });
for (int i = 0; i < someArray.Length; i++)
{
Console.WriteLine(someArray[i]); // correct value
Convert.ToDouble(someArray[i]); // error
}
采纳答案by Zbigniew
There are 3 problems.
有3个问题。
1) Incorrect decimal separator
1) 小数点分隔符不正确
Different cultures use different decimal separators (namely ,and .).
不同的文化使用不同的小数点分隔符（即,和.）。
If you replace .with ,it should work as expected:
如果你.用,它替换它应该按预期工作：
Console.WriteLine(Convert.ToDouble("52,8725945"));
You can parse your doubles using overloaded method which takes culture as a second parameter. In this case you can use InvariantCulture(What is the invariant culture) e.g. using double.Parse:
您可以使用重载方法解析双打，该方法将文化作为第二个参数。在这种情况下，您可以使用InvariantCulture（什么是不变文化），例如使用double.Parse：
double.Parse("52.8725945", System.Globalization.CultureInfo.InvariantCulture);
You should also take a look at double.TryParse, you can use it with many options and it is especially useful to check wheter or not your string is a valid double.
您还应该看看double.TryParse，您可以将它与许多选项一起使用，并且检查您的字符串是否有效特别有用double。
2) You have an incorrect double
2）你的双打不正确
One of your values is incorrect, because it contains two dots:
您的值之一不正确，因为它包含两个点：
15.5859949000000662452.23862099999999
15.5859949000000662452.23862099999999
3) Your array has an empty value at the end, which is an incorrect double
3) 你的数组最后有一个空值，这是一个不正确的双精度
You can use overloaded Splitwhich removes empty values:
您可以使用重载Split来删除空值：
string[] someArray = a.Split(new char[] { '#' }, StringSplitOptions.RemoveEmptyEntries);
string[] someArray = a.Split(new char[] { '#' }, StringSplitOptions.RemoveEmptyEntries);
回答by Rob I
In your string I see: 15.5859949000000662452.23862099999999which is not a double (it has two decimal points). Perhaps it's just a legitimate input error?
在您的字符串中，我看到：15.5859949000000662452.23862099999999这不是双精度数（它有两个小数点）。也许这只是一个合法的输入错误？
You may also want to figure out if your last Stringwill be empty, and account for that situation.
您可能还想弄清楚您的最后一个String是否为空，并说明这种情况。
回答by Ervi B
Most people already tried to answer your questions.
If you are still debugging, have you thought about using:
大多数人已经尝试回答您的问题。
如果还在调试，有没有想过使用：
Double.TryParse(String, Double);
This will help you in determining what is wrong in each of the string first before you do the actual parsing.
If you have a culture-related problem, you might consider using:
这将帮助您在进行实际解析之前首先确定每个字符串中有什么问题。
如果您有与文化相关的问题，您可以考虑使用：
Double.TryParse(String, NumberStyles, IFormatProvider, Double);
This http://msdn.microsoft.com/en-us/library/system.double.tryparse.aspxhas a really good example on how to use them.
这个http://msdn.microsoft.com/en-us/library/system.double.tryparse.aspx有一个关于如何使用它们的很好的例子。
If you need a long, Int64.TryParse is also available: http://msdn.microsoft.com/en-us/library/system.int64.tryparse.aspx
如果您需要很长的 Int64.TryParse，也可以使用：http: //msdn.microsoft.com/en-us/library/system.int64.tryparse.aspx
Hope that helps.
希望有帮助。
回答by bask0xff
private double ConvertToDouble(string s)
{
char systemSeparator = Thread.CurrentThread.CurrentCulture.NumberFormat.CurrencyDecimalSeparator[0];
double result = 0;
try
{
if (s != null)
if (!s.Contains(","))
result = double.Parse(s, CultureInfo.InvariantCulture);
else
result = Convert.ToDouble(s.Replace(".", systemSeparator.ToString()).Replace(",", systemSeparator.ToString()));
}
catch (Exception e)
{
try
{
result = Convert.ToDouble(s);
}
catch
{
try
{
result = Convert.ToDouble(s.Replace(",", ";").Replace(".", ",").Replace(";", "."));
}
catch {
throw new Exception("Wrong string-to-double format");
}
}
}
return result;
}
and successfully passed tests are:
并成功通过的测试是：
Debug.Assert(ConvertToDouble("1.000.007") == 1000007.00);
Debug.Assert(ConvertToDouble("1.000.007,00") == 1000007.00);
Debug.Assert(ConvertToDouble("1.000,07") == 1000.07);
Debug.Assert(ConvertToDouble("1,000,007") == 1000007.00);
Debug.Assert(ConvertToDouble("1,000,000.07") == 1000000.07);
Debug.Assert(ConvertToDouble("1,007") == 1.007);
Debug.Assert(ConvertToDouble("1.07") == 1.07);
Debug.Assert(ConvertToDouble("1.007") == 1007.00);
Debug.Assert(ConvertToDouble("1.000.007E-08") == 0.07);
Debug.Assert(ConvertToDouble("1,000,007E-08") == 0.07);
回答by Arun Prasad E S
Add a class as Public and use it very easily like convertToInt32()
添加一个类为 Public 并像 convertToInt32() 一样轻松使用它
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
/// <summary>
/// Summary description for Common
/// </summary>
public static class Common
{
public static double ConvertToDouble(string Value) {
if (Value == null) {
return 0;
}
else {
double OutVal;
double.TryParse(Value, out OutVal);
if (double.IsNaN(OutVal) || double.IsInfinity(OutVal)) {
return 0;
}
return OutVal;
}
}
}
Then Call The Function
然后调用函数
double DirectExpense = Common.ConvertToDouble(dr["DrAmount"].ToString());
回答by Asiamah Amos
You can try this example out. A simple C# progaram to convert string to double
你可以试试这个例子。一个简单的 C# 程序将字符串转换为双精度
class Calculations{
protected double length;
protected double height;
protected double width;
public void get_data(){
this.length = Convert.ToDouble(Console.ReadLine());
this.width = Convert.ToDouble(Console.ReadLine());
this.height = Convert.ToDouble(Console.ReadLine());
}
}
