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I looked and searched and couldn't find what I needed although I think it should be simple (if you have any Python experience, which I don't).
Given a string, I want to verify, in Python, that it contains ONLY alphanumeric characters: a-zA-Z0-9 and . _ -
examples:
Accepted:
bill-gates
Steve_Jobs
Micro.soft
Rejected:
Bill gates -- no spaces allowed
[email protected] -- @ is not alphanumeric
I'm trying to use:
if re.match("^[a-zA-Z0-9_.-]+$", username) == True:
But that doesn't seem to do the job...
365
For checking if a string consists only of alphanumerics using module regular expression or regex, we can call the re. match(regex, string) using the regex: "^[a-zA-Z0-9]+$". re. match returns an object, to check if it exists or not, we need to convert it to a boolean using bool().
The regex \w is equivalent to [A-Za-z0-9_] , matches alphanumeric characters and underscore.
fullmatch(). This method checks if the whole string matches the regular expression pattern or not. If it does then it returns 1, otherwise a 0.
re.match does not return a boolean; it returns a MatchObject on a match, or None on a non-match.
>>> re.match("^[a-zA-Z0-9_.-]+$", "hello")
<_sre.SRE_Match object at 0xb7600250>
>>> re.match("^[a-zA-Z0-9_.-]+$", " ")
>>> print re.match("^[a-zA-Z0-9_.-]+$", " ")
None
So, you shouldn't do re.match(...) == True; rather, you should be checking re.match(...) is not None in this case, which can be further shortened to just if re.match(...).
179
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