> I suggest that when you need this functionality you create your own data
> structure combining a list and a collections.Counter and keep track of
> this yourself.
I concur with the usage of collections.Counter here. Storing the count for
every single item in a list could end up being rather redundant with
duplicate elements, so Counter ends up being much more space efficient.
With it being implemented as a dictionary, the lookup speeds are incredibly
quick for getting an on-demand count for any item within it.
But, is it practically beneficial to combine the functionality of a list
and collections.Counter instead of just using both data structures together?
Here's a rough example of what I'm talking about. I recall using something
vaguely similar to this before:
```
items = [...]
counter = collections.Counter(items)
for item in items:
# use counter[item] instead of items.count(item)
if count := counter[item] > x:
# do something with item and its count
```
(Note: omit "count :=" if the count isn't needed for anything beyond the
conditional check)
On Wed, Jan 15, 2020 at 10:34 AM Eric V. Smith <e...@trueblade.com> wrote:
> On 1/14/2020 11:03 PM, Hunter Jones wrote:
> > Hey everyone,
> >
> > I recently used list.count() in a coding interview and the question
> > arose about how scale-able this solution was for sufficiently large
> > input. Currently, list.count iterates through the list, incrementing
> > the count as it goes and returning the value at the end. This does not
> > lend itself well to large inputs.
> >
> > I propose either modifying the list struct to include a map of item ->
> > count, or implementing a new structure with this information that is
> > allocated separately when a list is instantiated.
> >
> > Maybe I'm just seeing this since it's an edge case that I recently
> > dealt with, but I believe it would be a useful enhancement overall.
> >
> > Thoughts?
>
> That seems like a pretty niche requirement. In all of my years using
> Python I've never needed such a thing.
>
> I suggest that when you need this functionality you create your own data
> structure combining a list and a collections.Counter and keep track of
> this yourself.
>
> Eric
>
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