regexp search on infinite string?
John Machin
sjmachin at lexicon.net
Sat Sep 15 07:22:49 EDT 2007
On Sep 15, 4:36 pm, Paddy <paddy3... at googlemail.com> wrote:
> On Sep 15, 2:57 am, James Stroud <jstr... at mbi.ucla.edu> wrote:
>
>
>
> > Paddy wrote:
> > > Lets say i have a generator running that generates successive
> > > characters of a 'string'
> > >>From what I know, if I want to do a regexp search for a pattern of
> > > characters then I would have to 'freeze' the generator and pass the
> > > characters so far to re.search.
> > > It is expensive to create successive characters, but caching could be
> > > used for past characters. is it possible to wrap the generator in a
> > > class, possibly inheriting from string, that would allow the regexp
> > > searching of the string but without terminating the generator? In
> > > other words duck typing for the usual string object needed by
> > > re.search?
>
> > > - Paddy.
>
> > re.search & re.compile checks for str or unicode types explicitly, so
> > you need to turn your data into one of those before using the module.
Aaaarbejaysus. Since when?
>>> import array
>>> ba = array.array('c', 'A hollow voice says "Plugh".')
>>> import re
>>> mobj = re.search('voi', ba)
>>> mobj
<_sre.SRE_Match object at 0x00B99598>
>>> mobj.span()
(9, 12)
>>>
>
> > buffer = []
> > while True:
> > buffer.append(mygerator.next())
> > m = re.search(pattern, "".join(buffer))
> > if m:
> > process(m)
> > buffer = []
>
> > James
>
> Thanks James.
So:
buffer = array.array('c')
and flick the "".join() etc etc
HTH,
John
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