Dimitry Dimitry - 5 months ago 5
Python Question

Python regex match space only

In python3, how do I match exactly whitespace character and not newline \n or tab \t?

I've seen the

\s+[^\n]
answer from Regex match space not \n answer, but for the following example it does not work:

a='rasd\nsa sd'
print(re.search(r'\s+[^ \n]',a))


Result is
<_sre.SRE_Match object; span=(4, 6), match='\ns'>
, which is the newline matched.

Answer

If you want to match 1 or more whitespace chars except the newline and a tab use

r"[^\S\n\t]+"

The [^\S] matches any char that is not a non-whitespace = any char that is whitespace. However, since the character class is a negated one, when you add characters to it they are excluded from matching.

Python demo:

import re
a='rasd\nsa sd'
print(re.findall(r'[^\S\n\t]+',a))
# => [' ']

Some more considerations: \s matches [ \t\n\r\f\v] if ASCII flag is used. So, if you plan to only match ASCII, you might as well use [ \r\f\v] to exclude the chars you want. If you need to work with Unicode strings, the solution above is a viable one.