I have been experimenting with generators (e.g. in the form of Iterators.map
and (something... for x in 1:n)
) and finding that it can be very nice for composing separate parts of a calculation together and avoiding a bunch of intermediate allocations. However, I'm having a hard time creating generalized functions on them. I think the lack of a formal contract of "this object is an iterable" and not being able to peek into a generator's eltype
to dispatch are the specific reasons why I'm having a hard time. I think I also don't really see lazy iterators/generators used heavily in Julia. Should I just bite the bullet and focus on arrays? Not sure if it matters, but I'm speaking of various applications of survival arrays, timepoints, cashflows, etc from the JuliaActuary ecosystem.
it depends very heavily on what you're trying to do with iterators - if all your data is already tabular, staying tabular is going to be an advantage
I've had the same problem as you. My solution was to just not dispatch on iterators in my code. It sucks though.
Also agree. In case you missed it, there are a couple of holy-trait functions which can help in some cases: https://docs.julialang.org/en/v1/manual/interfaces/
I often do wonder why something like itertype
is not in that list though.
You can (in theory) always use eltype
as a "trait" for dispatching to an internal function, though be prepared to have a lengthy fallback for Any
..
Lazy calculations, arrays, tables - in Julia there's no need to choose, you easily get all three :)
julia> using FlexiMaps, Tables
julia> xs = 1:10
# apply lazily computed map
julia> ys = mapview(i -> (;i, i2=i^2), xs)
10-element ...:
(i = 1, i2 = 1)
(i = 2, i2 = 4)
...
# ys is an abstractvector with the correct eltype
julia> eltype(ys)
NamedTuple{(:i, :i2), Tuple{Int64, Int64}}
julia> ys isa AbstractVector
true
# and it's a table, so all Tables.jl integrations work
julia> columntable(ys)
(i = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10], i2 = [1, 4, 9, 16, 25, 36, 49, 64, 81, 100])
Last updated: Nov 22 2024 at 04:41 UTC