trying to match a string

oj ojeeves at gmail.com
Mon Jul 21 11:23:43 CEST 2008


On Jul 19, 3:04 am, Andrew Freeman <alif... at gmail.com> wrote:
> let me revise it please:
>
> To show if valid:
>
> if re.search(r'^[LRM]*$', 'LM'):
>     print 'Valid'

Fine, this works, although match instead of search blah blah blah as
has already been mentioned. I still think searching for one invalid
character is more elegant then trying to match the entire string, but
that's just personal preference, I guess.

>
> To show if invalid,
>
> if re.search(r'^[^LRM]*$', '0'):
>     print 'Inalid'

No. This is wrong. This only matches strings that consist entirely of
characters that are not L, R or M:

>>> import re
>>> if re.search(r'^[^LRM]*$', 'ZZZLZZZ'):
...     print "Invalid"
...
>>>

This doesn't print "Invalid" because there is one non-invalid
character there, which is clearly not what the OP wanted.



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