re Questions
Blake Adams
blakesadams at gmail.com
Sun Jan 26 12:15:51 EST 2014
On Sunday, January 26, 2014 12:08:01 PM UTC-5, Chris Angelico wrote:
> On Mon, Jan 27, 2014 at 3:59 AM, Blake Adams <blakesadams at gmail.com> wrote:
>
> > If I want to set up a match replicating the '\w' pattern I would assume that would be done with '[A-z0-9_]'. However, when I run the following:
>
> >
>
> > re.findall('[A-z0-9_]','^;z %C\@0~_') it matches ['^', 'z', 'C', '\\', '0', '_']. I would expect the match to be ['z', 'C', '0', '_'].
>
> >
>
> > Why does this happen?
>
>
>
> Because \w is not the same as [A-z0-9_]. Quoting from the docs:
>
>
>
> """
>
> \w For Unicode (str) patterns:Matches Unicode word characters; this
>
> includes most characters that can be part of a word in any language,
>
> as well as numbers and the underscore. If the ASCII flag is used, only
>
> [a-zA-Z0-9_] is matched (but the flag affects the entire regular
>
> expression, so in such cases using an explicit [a-zA-Z0-9_] may be a
>
> better choice).For 8-bit (bytes) patterns:Matches characters
>
> considered alphanumeric in the ASCII character set; this is equivalent
>
> to [a-zA-Z0-9_].
>
> """
>
>
>
> If you're working with a byte string, then you're close, but A-z is
>
> quite different from A-Za-z. The set [A-z] is equivalent to
>
> [ABCDEFGHIJKLMNOPQRSTUVWXYZ[\\]^_`abcdefghijklmnopqrstuvwxyz] (that's
>
> a literal backslash in there, btw), so it'll also catch several
>
> non-alphabetic characters. With a Unicode string, it's quite
>
> distinctly different. Either way, \w means "word characters", though,
>
> so just go ahead and use it whenever you want word characters :)
>
>
>
> ChrisA
Thanks Chris
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