We have two general ways to handle collections: we can use a higher-order function that returns a generator expression, or we can create a function that uses a for loop to process each item in a collection. The two essential patterns are very similar.
Following is a higher-order function that behaves like the built-in map() function:
from typing import Callable, Iterable, Iterator, Any, TypeVarD_ = TypeVar("D_")R_ = TypeVar("R_")def mapf( f: Callable[[D_], R_], C: Iterable[D_] ) -> Iterator[R_]: return (f(x) for x in C)
We've returned a generator expression that produces the required mapping. This uses the explicit for in the generator expression as a kind of tail-call optimization.
The source of data ...
