On Fri, 08 Nov 2013 12:48:12 -0500, Roy Smith wrote:
> I have a long string (several Mbytes). I want to iterate over it in
> manageable chunks (say, 1 kbyte each). For (a small) example, if I
> started with "this is a very long string", and I wanted 10 character
> chunks, I should get:
>
> "this is a "
> "very long "
> "string"
>
> This seems like something itertools would do, but I don't see anything.
> Is there something, or do I just need to loop and slice (and worry about
> getting all the edge conditions right) myself?
What edge conditions? Should be trivially easy to loop and slice:
def grouper(string, size):
i = 0
while i <= len(string):
yield string[i:i+size]
i += size
But if you prefer, there is a recipe in the itertools documentation to
solve this problem for you:
http://docs.python.org/2/library/itertools.html#recipes
It's short enough to reproduce here.
from itertools import izip_longest
def grouper(iterable, n, fillvalue=None):
"Collect data into fixed-length chunks or blocks"
# grouper('ABCDEFG', 3, 'x') --> ABC DEF Gxx
args = [iter(iterable)] * n
return izip_longest(fillvalue=fillvalue, *args)
grouper(your_string, 10, '')
ought to give you the results you want.
I expect (but haven't tested) that for strings, the slice version will be
faster.
--
Steven
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