C# 用逗号和点解析字符串以加倍
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Parse strings to double with comma and point
提问by metacircle
I am trying to write a function which basically converts an array of strings to an array of strings where all the doubles in the array are rounded to the number of decimalplaces i set. There can also be strings in the array which are no double values at all.
我正在尝试编写一个函数，该函数基本上将字符串数组转换为字符串数组，其中数组中的所有双精度数都四舍五入为我设置的小数位数。数组中也可以有根本不是双精度值的字符串。
string[,] values = new string[1, 3];
values[0, 0] = "hello";
values[0, 1] = "0.123";
values[0, 2] = "0,123";
int decimalPlaces = 2;
double tmp;
string format = "F" + decimalPlaces.ToString();
IFormatProvider provider = CultureInfo.InvariantCulture;
for (int i = 0; i < values.GetLength(0); i++)
{
for (int j = 0; j < values.GetLength(1); j++)
{
if (double.TryParse(values[i, j], out tmp))
{
values[i, j] = tmp.ToString(format, provider);
}
}
}
Console.ReadLine();
The result has to be: "hello" , "0.12", "0.12" but it is "hello", "123.00", "0.12" will treat the comma in the wrong way. Does anyone have a simple and efficient solution for this?
结果必须是： "hello" , "0.12", "0.12" 但它是 "hello", "123.00", "0.12" 将以错误的方式处理逗号。有没有人有一个简单有效的解决方案？
采纳答案by mmdemirbas
You want to treat dot (.) like comma (,). So, replace
您想将点 ( .)视为逗号 ( ,)。所以，更换
if (double.TryParse(values[i, j], out tmp))
with
和
if (double.TryParse(values[i, j].Replace('.', ','), out tmp))
回答by Paul Fleming
Use this overload of double.TryParse to specify allowed formats:
使用 double.TryParse 的重载来指定允许的格式：
Double.TryParse Method (String, NumberStyles, IFormatProvider, Double%)
Double.TryParse 方法（字符串、NumberStyles、IFormatProvider、Double%）
By default, double.TryParse will parse based on current culture specific formats.
默认情况下，double.TryParse 将根据当前的文化特定格式进行解析。
回答by Daniel A.A. Pelsmaeker
The problem is that you (or the system) cannot distinguish a decimal separator from a thousands separator when they can be both a comma or dot. For example:
问题是您（或系统）无法区分小数分隔符和千位分隔符，因为它们既可以是逗号也可以是点。例如：
In my culture,
1.123is a normal notation for a number above 1000; whereas
1,123is a number near 1.
在我的文化中，
1.123是大于 1000 的数字的正常表示法；然而
1,123是一个接近 1 的数字。
Using the invariant culture defaults to using the dot as a decimal separator. In general you should ensure that all numbers are written using the same constant culture on all systems (e.g. the invariant culture).
使用不变区域性默认使用点作为小数点分隔符。通常，您应该确保在所有系统上使用相同的恒定区域性（例如不变区域性）编写所有数字。
If you are sure that your numbers never contain anything other than a comma or dot for a decimal separator (i.e. no thousands separators), I'd String.Replace()the comma with a dot and do the rest as you did.
如果您确定您的数字除了逗号或小数点分隔符（即没有千位分隔符）之外从不包含任何其他内容，我会String.Replace()用一个点号逗号，然后像您一样做其余的事情。
Otherwise, you'll have a hard time programming something that can distinguish 1.123from 1,123without knowing the culture.
否则，您将很难编写一些可以1.123在1,123不了解文化的情况下区分的东西。
回答by Axxelsian
You can check if the string contains a decimal point using
您可以使用检查字符串是否包含小数点
string s="";
string s="";
if (s.Contains(','))
{
//treat as double how you wish
}
and then treat that as a decimal, otherwise just pass the non-double value along.
然后将其视为小数，否则只需传递非双精度值。
回答by hultqvist
To treat both , and . as decimal point you must not only replace one with the other, but also make sure the Culture used parsing interprets it as a decimal point.
对待 , 和 。作为小数点，您不仅必须将一个替换为另一个，还必须确保使用的文化解析将其解释为小数点。
text = text.Replace(',', '.');
return double.TryParse(text, NumberStyles.Any, CultureInfo.InvariantCulture, out value);
回答by OliverAssad
You DO NOT NEED to replace the comma and dot..
你不需要替换逗号和点..
I have had the very same problem. The reason is simple, the conversion culture plays a big role in which the comma or a dot is interpreted. I use a German culture where the comma distinguish the fractions, where as elsewhere the dot does the job.
我遇到了同样的问题。原因很简单，转换文化在其中解释逗号或点的作用很大。我使用德国文化，其中逗号区分分数，而在其他地方，点可以完成这项工作。
Here I made a complete example to make the difference clear.
这里我做了一个完整的例子来说明区别。
string[] doubleStrings = {"hello", "0.123", "0,123"};
double localCultreResult;
foreach (var doubleString in doubleStrings)
{
double.TryParse(doubleString, NumberStyles.Any, CultureInfo.CurrentCulture, out localCultreResult);
Console.WriteLine(string.Format("Local culture results for the parsing of {0} is {1}", doubleString, localCultreResult));
}
double invariantCultureResult;
foreach (var doubleString in doubleStrings)
{
double.TryParse(doubleString, NumberStyles.Any, CultureInfo.InvariantCulture, out invariantCultureResult);
Console.WriteLine(string.Format("Invariant culture results for the parsing of {0} is {1}", doubleString, invariantCultureResult));
}
The results is the following:
结果如下：
Play around with the culture and you will get the result you need.
玩转文化，你会得到你需要的结果。
回答by diegoguevara
try this... it works for me.
试试这个……它对我有用。
double vdouble = 0;
string sparam = "2,1";
if ( !Double.TryParse( sparam, NumberStyles.Float, CultureInfo.InvariantCulture, out vdouble ) )
{
if ( sparam.IndexOf( '.' ) != -1 )
{
sparam = sparam.Replace( '.', ',' );
}
else
{
sparam = sparam.Replace( ',', '.' );
}
if ( !Double.TryParse( sparam, NumberStyles.Float, CultureInfo.InvariantCulture, out vdouble ) )
{
vdouble = 0;
}
}
回答by Andrew
Extension to parse decimal number from string.
从字符串解析十进制数的扩展。
- No matter number will be on the beginning, in the end, or in the middle of a string.
- No matter if there will be only number or lot of "garbage" letters.
- No matter what is delimiter configured in the cultural settings on the PC: it will parse dot and comma both correctly.
Ability to set decimal symbol manually.
public static class StringExtension { public static double DoubleParseAdvanced(this string strToParse, char decimalSymbol = ',') { string tmp = Regex.Match(strToParse, @"([-]?[0-9]+)([\s])?([0-9]+)?[." + decimalSymbol + "]?([0-9 ]+)?([0-9]+)?").Value; if (tmp.Length > 0 && strToParse.Contains(tmp)) { var currDecSeparator = System.Windows.Forms.Application.CurrentCulture.NumberFormat.NumberDecimalSeparator; tmp = tmp.Replace(".", currDecSeparator).Replace(decimalSymbol.ToString(), currDecSeparator); return double.Parse(tmp); } return 0; } }
- 无论数字是在字符串的开头、结尾还是中间。
- 无论是只有数字还是大量的“垃圾”字母。
- 无论在 PC 上的文化设置中配置了什么分隔符：它都会正确解析点和逗号。
能够手动设置十进制符号。
public static class StringExtension { public static double DoubleParseAdvanced(this string strToParse, char decimalSymbol = ',') { string tmp = Regex.Match(strToParse, @"([-]?[0-9]+)([\s])?([0-9]+)?[." + decimalSymbol + "]?([0-9 ]+)?([0-9]+)?").Value; if (tmp.Length > 0 && strToParse.Contains(tmp)) { var currDecSeparator = System.Windows.Forms.Application.CurrentCulture.NumberFormat.NumberDecimalSeparator; tmp = tmp.Replace(".", currDecSeparator).Replace(decimalSymbol.ToString(), currDecSeparator); return double.Parse(tmp); } return 0; } }
How to use:
如何使用：
"It's 4.45 O'clock now".DoubleParseAdvanced(); // will return 4.45
"It's 4,45 O'clock now".DoubleParseAdvanced(); // will return 4.45
"It's 4:45 O'clock now".DoubleParseAdvanced(':'); // will return 4.45
回答by Sinipelto
Make two static cultures, one for comma and one for point.
制作两种静态文化，一种用于逗号，一种用于点。
var commaCulture = new CultureInfo("en")
{
NumberFormat =
{
NumberDecimalSeparator = ","
}
};
var pointCulture = new CultureInfo("en")
{
NumberFormat =
{
NumberDecimalSeparator = "."
}
};
Then use each one respectively, depending on the input (using a function):
然后根据输入分别使用每一个（使用函数）：
public double ConvertToDouble(string input)
{
input = input.Trim();
if (input == "0") {
return 0;
}
if (input.Contains(",") && input.Split(',').Length == 2)
{
return Convert.ToDouble(input, commaCulture);
}
if (input.Contains(".") && input.Split('.').Length == 2)
{
return Convert.ToDouble(input, pointCulture);
}
throw new Exception("Invalid input!");
}
Then loop through your arrays
然后遍历你的数组
var strings = new List<string> {"0,12", "0.122", "1,23", "00,0", "0.00", "12.5000", "0.002", "0,001"};
var doubles = new List<double>();
foreach (var value in strings) {
doubles.Add(ConvertToDouble(value));
}
This should work even though the host environment and culture changes.
即使宿主环境和文化发生变化，这也应该有效。
