How do I get the value in between 2 strings? I have a string with format d1048_m325 and I need to get the value between d and _. How is this done in C#?
Thanks,
Mike
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Will everytime you will be required the string between d and _ only. or that will be different in different cases?Bhavik Goyal– Bhavik Goyal2011-02-04 10:13:22 +00:00Commented Feb 4, 2011 at 10:13
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4 Answers
(?<=d)\d+(?=_)
should work (assuming that you're looking for an integer value between d and _):
(?<=d) # Assert that the previous character is a d
\d+ # Match one or more digits
(?=_) # Assert that the following character is a _
In C#:
resultString = Regex.Match(subjectString, @"(?<=d)\d+(?=_)").Value;
1 Comment
Tedd Hansen
And remember that precompiled regexes are a valuable source of proteins. :)
Alternatively if you want more freedom as to what can be between the d and _:
d([^_]+)
which is
d # Match d
([^_]+) # Match (and capture) one or more characters that isn't a _
Even though the regex answers found on this page are probably good, I took the C# approach to show you an alternative. Note that I typed out every step so it's easy to read and to understand.
//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);
1 Comment
Nick
I know that Substrings/indexOfs are faster than regular expressions. I'd be interested to know how two IndexOfs and a Substring compared to one regex in C# though.
You can also use lazy quantifier
d(\d+?)_
