Here's a one-line version:
from itertools import groupby
rle_encode = lambda it: (
(l[0],len(l)) for g in groupby(it) for l in [list(g[1])])
Since "not every one line function needs to be in the standard library" is
a guiding principle of Python, and even moreso of `itertools`, probably
this is a recipe in the documentation at most. Or maybe it would have a
home in `more_itertools`.
On Sat, Jun 10, 2017 at 7:20 PM, Neal Fultz <nfu...@gmail.com> wrote:
> Hello python-ideas,
>
> I am very new to this, but on a different forum and after a couple
> conversations, I really wished Python came with run-length encoding
> built-in; after all, it ships with zip, which is much more complicated :)
>
> The general idea is to be able to go back and forth between two
> representations of a sequence:
>
> [1,1,1,1,2,3,4,4,3,3,3]
>
> and
>
> [(1, 4), (2, 1), (3, 1), (4, 2), (3, 3)]
>
> where the first element is the data element, and the second is how many
> times it is repeated.
>
> I wrote an encoder/decoder in about 20 lines (
> https://github.com/nfultz/rle.py/blob/master/rle.py ) and would like to
> offer it for the next version; I think it might fit in nicely in the
> itertools module, for example. I am curious about your thoughts.
>
> Best,
>
> -Neal
>
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