I want to match space chars or end of string in a text.
import re
uname='abc'
assert re.findall('@%s\s*$' % uname, '@'+uname)
assert re.findall('@%s\s*$' % uname, '@'+uname+' '+'aa')
assert not re.findall('@%s\s*$' % uname, '@'+uname+'aa')
The pattern is not right.
How to use python?
\\s*$
is incorrect: this matches "zero or more spaces followed by the end of the string", rather than "one or more spaces or the end of the string".
For this situation, I would use (?:\\s+|$)
(inside a raw string, as others have mentioned). The (?:)
part is just about separating that subexpression so that the | operator matches the correct fragment and no more than the correct fragment.
Try this:
assert re.findall('@%s\\s*$' % uname, '@'+uname)
You must escape the \\
character if you don't use raw strings.
It's a bit confusing, but stems from the fact that \\
is a meta character for both the python interpreter and the re
module.
Use raw strings .
assert re.findall(r'@%s\s*$' % uname, '@'+uname)
Otherwise the use of \\
as a special character in regular strings conflicts with its use as a special character in regular expressions.
But this assertion is impossible to fail. Of course, a string consisting of nothing but "@" plus the contents of the variable uname
is going to match a regular expression of "@" plus uname
plus optional (always empty) whitespace and then the end of the string. It's a tautology. I suspect you are trying to check for something else?
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