[Python-ideas] Run length encoding

[Bernardo Sulzbach]

On 2017-06-10 23:20, Neal Fultz 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.
>
We can currently do it like this in one line:

     [(k, sum(1 for _ in g)) for k, g in groupby(sequence)]

However, it is slower than a "dedicated" solution.

Additionally, I don't know if what you are proposing is generic enough 
for the standard library.

-- 
Bernardo Sulzbach
http://www.mafagafogigante.org/
mafagafogigante at gmail.com