2个字符串之间的正则表达式值

Question

如何获取2个字符串之间的值？我有一个格式为d1048_m325的字符串，我需要得到d和_之间的值。这是如何在C＃中完成的？

感谢，

迈克

Answer 1

(?<=d)\d+(?=_) 

应该工作（假设你正在寻找d和_之间的整数）：

(?<=d) # Assert that the previous character is a d 
\d+ # Match one or more digits 
(?=_) # Assert that the following character is a _ 

在C＃：

resultString = Regex.Match(subjectString, @"(?<=d)\d+(?=_)").Value; 

Answer 2

或者，如果你想要更多的自由，什么可以是d和_之间：

d([^_]+) 

这是

d  # Match d 
([^_]+) # Match (and capture) one or more characters that isn't a _ 

Answer 3

您还可以使用惰性限定符

d（\ d +？）_

Answer 4

尽管在本页找到了正则表达式的答案可能是好的，我采用了C＃方法来向你展示一个替代方案。请注意，我输入了每一步，因此很容易阅读和理解。

//your string 
string theString = "d1048_m325"; 

//chars to find to cut the middle string 
char firstChar = 'd'; 
char secondChar = '_'; 

//find the positions of both chars 
//firstPositionOfFirstChar +1 to not include the char itself 
int firstPositionOfFirstChar = theString.IndexOf(firstChar) +1; 
int firstPositionOfSecondChar = theString.IndexOf(secondChar); 

//the middle string will have a length of firstPositionOfSecondChar - firstPositionOfFirstChar 
int middleStringLength = firstPositionOfSecondChar - firstPositionOfFirstChar; 

//cut! 
string middle = theString.Substring(firstPositionOfFirstChar, middleStringLength);