从字符串读取一个double值 [英] Reading a double value from a string

问题描述

我试图来解决这个几个小时，完全不明白编译器在这里做。我有串，基本上是这样的：

 KL10124叛徒＃2  -  + XX-+ 0.25  - 更多的东西
 

和需要读出双'0.25'编程。调用上述S中的字符串，下面的两行不工作：

 的String [] H = s.Split（' - '）;
串H 2 = H [2] .Substring（1中，h [2] .Length  -  2）;
双D = Convert.ToDouble（H2）;
 

如果我显示输出的结果是25。我想这可能取决于'。 RESP，依赖文化，但如果我插入

 双D = Convert.ToDouble（h2.Replace（''）'。'）;
 

它不会改变任何事情，输出仍然是25。

但最后，如果我做的蛮力方法如下我得到的屏幕上逐字输出0.25

 双D;
字符串[] H = s.Split（' - '）;
串H 2 = H [2] .Substring（1中，h [2] .Length  -  2）;
如果（h2.Contains（。））
{
    字符串[] H3 = h2.Split（'。'）;
    D = Convert.ToDouble（H3 [0]）+ Convert.ToDouble（H3 [1]）/ 100;
}
其他
{
    D = Convert.ToDouble（H2）;
}
返回D组;
 

到底为什么做了前两个版本无法正常工作？的code中的最后一位不能做到这一点的正确方法。

解决方案

尝试使用

 双D = Convert.ToDouble（H2，CultureInfo.InvariantCulture）;
 

而不是

 双D = Convert.ToDouble（H2）;
 

I've tried to solve this for hours and absolutely don't understand what the compiler is doing here. I have strings that basically look like this:

"KL10124 Traitor #2 - +XX-+0.25 - More Stuff"

and need to read off the double '0.25' programmatically. Calling the string above s, the following two lines don't work:

string[] h = s.Split('-');
string h2 = h[2].Substring(1,h[2].Length - 2);
double d = Convert.ToDouble(h2);

The output if I display d is "25". I thought it might depend on the '.' resp ',' culture dependency, but if I insert

double d = Convert.ToDouble(h2.Replace('.',','));

it does not change a thing, the output is still "25".

But finally, if I do the brute force method as below I get the verbatim output "0,25" on the screen

double d;
string[] h = s.Split('-');
string h2 = h[2].Substring(1,h[2].Length - 2);
if (h2.Contains("."))
{
    string[] h3 = h2.Split('.');
    d = Convert.ToDouble(h3[0]) + Convert.ToDouble(h3[1])/100;
}
else
{
    d = Convert.ToDouble(h2);
}
return d;

Why exactly do the first two versions not work? The last bit of code cannot be the correct way to do this.

解决方案

Try to use

double d = Convert.ToDouble(h2, CultureInfo.InvariantCulture);

instead of

double d = Convert.ToDouble(h2);

这篇关于从字符串读取一个double值的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！