Regex: Remove all special characters that are not apostrophes between letters
Question:
I have a string like so:
s = "i'm sorry, sir, but this is a 'gluten-free' restaurant. we don't serve bread."
and I am trying to use re.sub to replace all special characters that are not apostrophes between letters with a space, so ‘gluten-free’ becomes gluten free and i’m will stay as i’m.
I have tried this:
import re
s = re.sub('[^[a-z]+'?[a-z]+]', ' ', s)
which I am trying to say is to replace anything that is not following the pattern of one and more letters, with then 0 or one apostrophes, followed by one or more letters with white space.
this returns the same string:
i'm sorry, sir, but this is a 'gluten-free' restaurant. we don't serve bread.
I would like to have:
i'm sorry sir but this is a gluten free restaurant we don't serve bread
Answers:
You may use this regex with a nested lookahead+lookbehind:
>>> s = "i'm sorry, sir, but this is a 'gluten-free' restaurant. we don't serve bread."
>>> print ( re.sub(r"(?!(?<=[a-z])'[a-z])[^ws]", ' ', s, flags=re.I) )
i'm sorry sir but this is a gluten free restaurant we don't serve bread
RegEx Details:
(?!: Start negative lookahead
(?<=[a-z]): Positive lookbehind to assert that we have an alphabet at previous position': Match an apostrophe[a-z]: Match letter [a-z]
): End negative lookahead[^ws]: Match a character that is not a whitespace and not a word character
You can use
import re
s = "i'm sorry, sir, but this is a 'gluten-free' restaurant. we don't serve bread."
print( re.sub(r"(?:(?!b['‘’]b)[W_])+", ' ', s).strip() )
# => i'm sorry sir but this is a gluten free restaurant we don't serve bread
See the Python demo and the regex demo.
Details:
(?: – start of a non-capturing group:
(?!b['‘’]b) – a negative lookahead that fails the match if there is an apostrophe within word chars[W_] – a non-word or _ char
)+ – one or more occurrences
I have a string like so:
s = "i'm sorry, sir, but this is a 'gluten-free' restaurant. we don't serve bread."
and I am trying to use re.sub to replace all special characters that are not apostrophes between letters with a space, so ‘gluten-free’ becomes gluten free and i’m will stay as i’m.
I have tried this:
import re
s = re.sub('[^[a-z]+'?[a-z]+]', ' ', s)
which I am trying to say is to replace anything that is not following the pattern of one and more letters, with then 0 or one apostrophes, followed by one or more letters with white space.
this returns the same string:
i'm sorry, sir, but this is a 'gluten-free' restaurant. we don't serve bread.
I would like to have:
i'm sorry sir but this is a gluten free restaurant we don't serve bread
You may use this regex with a nested lookahead+lookbehind:
>>> s = "i'm sorry, sir, but this is a 'gluten-free' restaurant. we don't serve bread."
>>> print ( re.sub(r"(?!(?<=[a-z])'[a-z])[^ws]", ' ', s, flags=re.I) )
i'm sorry sir but this is a gluten free restaurant we don't serve bread
RegEx Details:
(?!: Start negative lookahead(?<=[a-z]): Positive lookbehind to assert that we have an alphabet at previous position': Match an apostrophe[a-z]: Match letter[a-z]
): End negative lookahead[^ws]: Match a character that is not a whitespace and not a word character
You can use
import re
s = "i'm sorry, sir, but this is a 'gluten-free' restaurant. we don't serve bread."
print( re.sub(r"(?:(?!b['‘’]b)[W_])+", ' ', s).strip() )
# => i'm sorry sir but this is a gluten free restaurant we don't serve bread
See the Python demo and the regex demo.
Details:
(?:– start of a non-capturing group:(?!b['‘’]b)– a negative lookahead that fails the match if there is an apostrophe within word chars[W_]– a non-word or_char
)+– one or more occurrences