вс, 3 февр. 2019 г. в 21:23, David Mertz <[email protected]>: > > I think the principled thing to do here is add the minimal number of > methods to Vector itself, and have everything else pass through as > vectorized calls. Most of that minimal number are "magic method": > __len__(), __contains__(), __str__(), __repr__(), __iter__(), > __reversed__(). I might have forgotten a couple. All of those should not > be called directly, normally, but act as magic for operators or built-in > functions. > > I think I should then create regular methods of the same name that perform > the vectorized version. So we would have: > > len(v) # -> 12 > > v.len() # -> <Vector of [3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3]> > > list(v) # -> ["Jan", "Feb", "Mar", "Apr", "May", "Jul" ...] > v.list() # -> <Vector of [["J", "a", "n"], ["F", "e", "b"] ... > > > > Hi David! Thank you for taking the time to implement this idea. Sorry, I'm on a trip now and can't try it. From what I've read in this thread, I think I mostly agree with your perception how the vector should work: that `len(v) # -> 12` and that `.some_method()` call must apply to elements (although pedants may argue that in this case there is not much difference). The only moment that I don’t like is `v.len(), v.list() and ...`, for the same reasons - in general this will not work. I also don't like the option with `.apply` - what if `.apply` method is already defined for elements in a vector?
> I can't implement every single constructor that users might > conceivably want, of course, but I can do it for the basic types in > builtins and common standard library. E.g. I might do: > > v.deque() # -> <Vector of [deque(["J", "a", "n"]), deque(["F", "e", "b"]) > ... > > > > But I certainly won't manually add: > > v.custom_linked_list() # From my_inhouse_module.py > > > Hmm... maybe even I could look at names of maybe-constructors in the > current namespace and try them. That starts to feel too magic. Falling > back to this feels better: > > map(custom_linked_list, v) # From my_inhouse_module.py > > > Actually my thoughts on this. At first I thought that for these purposes it is possible to use __call__: len(v) # -> 12 v(len) # -> <Vector of [3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3]> But it somehow this idea did not fit in my head. Then I found the next way and I think I even like it - to reuse the `__getitem__`, when its argument is a function it means that you apply this function to every element in the vector. len(v) # -> 12 v[len] # -> <Vector of [3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3]> In this case you can apply any function, even custom_linked_list from my_inhouse_module.py. From this stream I did not understand what desired behavior for unary operations like `vector + 1` and the others. Also what is the desired behaviour for `vector[1:5]`? Considering the above, I would like to take this operation on the contrary: >>> v <Vector of ['Jan', 'Feb', 'Mar', 'Apr', 'May', 'Jun', 'Jul', 'Aug', 'Sep', 'Oct', 'Nov', 'Dec']> >>> v[1:] <Vector of ['Feb', 'Mar', 'Apr', 'May', 'Jun', 'Jul', 'Aug', 'Sep', 'Oct', 'Nov', 'Dec']> >>> v[i[1:]] # some helper class `i` <Vector of ['an', 'eb', 'ar', 'pr', 'ay', 'un', 'ul', 'ug', 'ep', 'ct', 'ov', 'ec']> With kind regards, -gdg
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