\b in python's re and exact word match

Question

How to make \\b properly respect the word boundary? For example, understand the ' and not does partial match...

>>> import re
>>> str = "This is a test's test"
>>> p1 = r'\b' + 'test' + r'\b'
>>> re.findall(p1,str)
['test', 'test']

Answer 1

Using negative look-ahead assertion , you can assure matching test that is not followed by ' .

>>> import re
>>> s = "This is a test's test"
>>> re.findall(r"\btest\b(?!')", s)  # match `test` as long as it is not followed by "'"
['test']

BTW, do not use str as a variable name. It shadows built-in function/type str .