正则表达式替换文件中的数字

There are a lot of numbers like 200 20.5 329.2...in a file. Now, I need replace every number A with A*0.8. Is there any simple method to replace original value with another based on original value?

在文件中有很多像200 20.5 329.2 ...的数字。现在,我需要用A * 0.8替换每个数字A.是否有任何简单的方法可以根据原始值替换原始值?

Best Regards,

2 个解决方案

#1

Try this one:

试试这个:

String s = "This is the number 2.5. And this is 7";
s = Regex.Replace(s, @"[+-]?\d+(\.\d*)?", m => {return (Double.Parse(m.ToString())*0.8).ToString();});
// s contains "This is the number 2. And this is 5.6"

Edit: Added the plus/minus sign as an optional character in front. To avoid catching the 5 in 3-5 as negative, you could use ((?<=\s)[+-])? instead of [+-]

编辑:在前面添加加号/减号作为可选字符。为了避免将3-5中的5作为负数,你可以使用((?<= \ s)[+ - ])?而不是[+ - ]

#2

Using lambda and slightly better handling of cases like The value is .5. Next sentence:

使用lambda并稍微更好地处理案例,如值为.5。下一句话:

var s = "This is the number 2.5. And this is 7, .5, 5. Yes.";
var result = Regex.Replace(s, @"[+-]?(\d*\.)?\d+", m => (double.Parse(m.Value) * 0.8).ToString());

#1