Given 2 callables checking when a condition arises and returning True: def starting_when(element): ... def ending_when(element: ... Allow: a_list[starting_when:] To be equivalent to: from itertools import dropwhile list(dropwhile(lambda x: not starting_when(x), a_list)) And: a_list[:ending_when] To: from itertools import takewhile list(takewhile(lambda x: not ending_when(x), a_list))
On 9 June 2018 at 19:20, Michel Desmoulin <desmoulinmichel@gmail.com> wrote:
Custom container implementations can already do this if they're so inclined, as slice objects don't type check their inputs: >>> class MyContainer: ... def __getitem__(self, key): ... return key ... >>> mc = MyContainer() >>> mc[:bool] slice(None, <class 'bool'>, None) >>> mc[bool:] slice(<class 'bool'>, None, None) >>> mc[list:tuple:range] slice(<class 'list'>, <class 'tuple'>, <class 'range'>) It's only slice.indices() that needs start/stop/step to adhere to the Optional[int] type hint. Cheers, Nick. -- Nick Coghlan | ncoghlan@gmail.com | Brisbane, Australia
On 9 June 2018 at 19:20, Michel Desmoulin <desmoulinmichel@gmail.com> wrote:
Custom container implementations can already do this if they're so inclined, as slice objects don't type check their inputs: >>> class MyContainer: ... def __getitem__(self, key): ... return key ... >>> mc = MyContainer() >>> mc[:bool] slice(None, <class 'bool'>, None) >>> mc[bool:] slice(<class 'bool'>, None, None) >>> mc[list:tuple:range] slice(<class 'list'>, <class 'tuple'>, <class 'range'>) It's only slice.indices() that needs start/stop/step to adhere to the Optional[int] type hint. Cheers, Nick. -- Nick Coghlan | ncoghlan@gmail.com | Brisbane, Australia
participants (2)
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Michel Desmoulin -
Nick Coghlan