Regular Expression for searching a string starting with string 1, does not containing string 2, and ends in string 3

Question

I'm currently writing a regular expression to search in files using visual studio regex pattern, the pattern im working on is something like this

starts with string 1
doesnt contain string2 in between strings 1 and 3
ends with string 3

Im modifying a previous regex that i used sometime ago (2 years?) but can't come up with something that fits the need. This is currently im trying to work on.

\bword1\W+(?:\w+\W+)*^((?!word2).)*$word3\b

Can anyone teach me a thing or two about regex?

Thank you

If string 3 contains within it string 2, is that allowed or not allowed? — Tim Biegeleisen, Jun 13 '17 at 02:39
Is regexp a must? Don't think regexp is required to achieve what you want. — Chris Lam, Jun 13 '17 at 02:40
Try `string1(?:(?!string1|string2).)*string3` or `string1(?:(?!string2).)*string3` — , Jun 13 '17 at 02:54
@TimBiegeleisen as per my requirement, the real world string2 isnt contained in string 3, so to answer, not allowed. — user1465073, Jun 13 '17 at 03:03
@ChrisLam, yes string2 should not be contained in/ between strings 1 and 3, the reason regexp is required is we're going to search within files using Visual Studio find in files, and the files is around 10000 or more files. — user1465073, Jun 13 '17 at 03:06

score 2 · Accepted Answer · answered Jun 13 '17 at 07:45

Look:

starts with string 1 - string1
doesn't contain string2 in between strings 1 and 3 - here, you need to use a . tempered with a negative lookahead - (?:(?!string1|string2).)*? (note that to match across line, in Visual Studio S&R you need to use [\s\S\r] instead of a . (\r is necessary here for the reason [\s\S] does not match a line break in VS S&R regex))
ends with string 3 - string3.

So, the whole expression is

string1(?:(?!string1|string2).)*?string3

See the regex demo.

Regular Expression for searching a string starting with string 1, does not containing string 2, and ends in string 3

1 Answers1