Well there is already a function you can call for these, __getitem__:
lst_getter = lst.__getitem__
map( lst_getter, idxs)
sorted(range(len(lst)), key=lst_getter)
max(range(len(lst)), key=lst_getter)
dct_getter = dct.__getitem__
map(dct, lst) instead of (dct[l] for l in lst)
If you find yourself preferring this map() style of code a lot (rather than
using generator expressions), you can make a utility function:
def getter(obj):
return obj.__getitem__
If anything is going to be proposed, I'd suggest rather than making these
callable directly, add a utility function that calls the dunder method.
So:
len() is to __len__
as:
getter() is to __getitem__
But I'm not proposing this, I'm just suggesting it as a bit better
alternative to the initial idea.
---
Ricky.
"I've never met a Kentucky man who wasn't either thinking about going home
or actually going home." - Happy Chandler
On Mon, Oct 5, 2020 at 8:42 AM <[email protected]> wrote:
> Hi all,
>
> I've been working in q and k, which is where this idea comes from.
>
> My idea is to make lists and dicts callable, with __call__ =
> __getitem__.
>
> So that:
>
> [3,4,5](1) gives 4
> {'a':1, 'b': 2}('b') gives 2
>
> Arguably a list is a function which maps from range(len(list)) to the
> list entries, and a dictionary is a function that maps from keys to
> values.
>
> This would mean that functions designed to take functions, can be
> repurposed to take data, for example:
>
> map(lst, idxs) instead of (lst[i] for i in idxs) or map(lambda x:
> lst[x], idxs)
> map(dct, lst) instead of (dct[l] for l in lst)
>
> sorted(range(len(lst)), key=lst) to calculate the equivalent of
> np.argsort
> max(range(len(lst)), key=lst) to calculate the equivalent of np.argmax
>
> I couldn't find this being discussed before. Does anyone like it? There
> is room for confusion as it would mean that e.g. filter([1,2], [0,1])
> would give [0,1] whilst [1] might be expected.
>
> Best,
>
> George Harding
>
> p.s. Thank you to everyone for their work on such a wonderful language.
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