Is there a way of retrieving a pattern inside a regular expression in Python? eg.:
strA = '\ta -- b'
and I would like to retrieve 'a' and 'b' into different variables
2 Answers
Sounds like you are talking about saving/capturing groups:
>>> import re
>>> pattern = r"\t(\w+) -- (\w+)"
>>> s = ' test1 -- test2'
>>> a, b = re.search(pattern, s).groups()
>>> a
'test1'
>>> b
'test2'
1 Comment
OnlineCop
Should
\t be \\t ?You can't retrieve a pattern, you can match or retrieve a capturing group content matching your pattern.
Following your example:
\ta -- b
If you want to retrieve the content you can use capturing groups using parentheses like:
\t(a) -- (b)
The regex explanation for this is:
\t '\t' (tab)
( group and capture to \1:
a 'a'
) end of \1
-- ' -- '
( group and capture to \2:
b 'b'
) end of \2
Then you would be able to grab group content by accesing then through its index like \1 (or $1) and group \2 (or $2). But you are going to grab the matched content, not the pattern itself.
So, if you have:
\t(\w) -- (\d)
You would grab content that matches that pattern:
\t '\t' (tab)
( group and capture to \1:
\w word characters (a-z, A-Z, 0-9, _)
) end of \1
-- ' -- '
( group and capture to \2:
\d digits (0-9)
) end of \2
But you can't retrieve \w or \d itself.
If you want to get the patterns for this:
\t\w -- \d
You should split above string by -- and you would get strings::
"\t\w "
" \d"
(?<=\\t)(\w+\b).*?(\b\w+\b)(example: regex101.com/r/fW1fV7/1)\t? Will the two always be separated by ` -- `? Will there be multiple patterns within the string, or will there only ever be 2?