Thomas Lotze wrote:
> I can see two possibilities to do this: either the current file position
> has to be read from somewhere (say, a mutable object passed to the
> generator) after each yield, or a new generator needs to be instantiated
> every time the tokenizer is pointed to a new file position.
>...
> Does anybody here have a third way of dealing with this? Otherwise,
> which ugliness is the more pythonic one?
The third approach, which is certain to be cleanest for this situation,
is to have a custom class which stores the state information you need,
and have the generator simply be a method in that class. There's no
reason that a generator has to be a standalone function.
class PdfTokenizer:
def __init__(self, ...):
# set up initial state
def getTokens(self):
while whatever:
yield token
def seek(self, newPosition):
# change state here
# usage:
pdf = PdfTokenizer('myfile.pdf', ...)
for token in pdf.getTokens():
# do stuff...
if I need to change position:
pdf.seek(...)
Easy as pie! :-)
-Peter
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