I'm trying to write a regex pattern that will fail a match if the preceding pattern contains any character except pure whitespace, for example
--hello (match)
--goodbye (match)
ROW_NUMBER() OVER (ORDER BY DATE) --date (fail)
--comment with some indentation (match)
--another comment with some indentation (match)
The closest I've got to is with this pattern I made (?<!.)--.*\n
, that gives me this result
--hello (match)
--goodbye (match)
ROW_NUMBER() OVER (ORDER BY DATE) --date (fail)
--comment with some indentation (fail)
--another comment with some indentation (fail)
I've tried (?<!\s)--.*\n
and (?<=\S)--.*\n
but both return no matches at all
EDIT: a regexr.com illustrating the issue more clearly regexr.com/6j0mt
With PyPi
regex
, you can useSee this Python demo online.
Or, with the default Python
re
:See this Python demo.
Pattern details
(?<=^[^\S\r\n]*)
- a positive lookbehind that matches a location that is immediately preceded with start of string/line and zero or more horizontal whitespaces^
- start of a string (here, a line, becausere.M
/regex.M
option is used)[^\S\r\n]*
- zero or more chars other than non-whitespace, CR and LF chars (any whitespace but carriage returns and line feed chars)(--.*)
- Group 1:--
and the rest of the line (.*
matches zero or more chars other than line break chars as many as possible).