New package: ProductArrays v1.0.0

[JuliaRegistrator]

• Registering package: ProductArrays
• Repository: https://github.com/lazyLibraries/ProductArrays.jl
• Created by: @github-actions[bot]
• Version: v1.0.0
• Commit: ef44acd36ba3c03a34c18b6d866b203cb7c79afe
• Reviewed by: @github-actions[bot]
• Reference: lazyLibraries/ProductArrays.jl@ef44acd#commitcomment-116062400
• Description: A lazy array acting like collect(Iterators.product(it...))

[github-actions]

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[aplavin]

There are at least three packages that do similar things already. In the order of registration date and increasing functionality: StructuredGrids, LazyGrids, RectiGrids.
Do really none of them suit your usecase? What's the difference of ProductArrays?

[noblock]

[FelixBenning]

There are at least three packages that do similar things already. In the order of registration date and increasing functionality: StructuredGrids, LazyGrids, RectiGrids. Do really none of them suit your usecase? What's the difference of ProductArrays? @aplavin

I actually didn't know about them - thanks for pointing them out. I didn't know I should search for "grid". RectiGrid actually doesn't behave the same as collected Iterators.product though (that is the single promise of this package)

julia> grid(1:2, (:a, :b))
ERROR: MethodError: no method matching grid(::UnitRange{Int64}, ::Tuple{Symbol, Symbol})
Closest candidates are:
  grid(::AbstractVector...) at ~/.julia/packages/RectiGrids/K7F4a/src/RectiGrids.jl:88
Stacktrace:
 [1] top-level scope
   @ REPL[24]:1

julia> grid([1 2; 3 4], (:a, :b))
ERROR: MethodError: no method matching grid(::Matrix{Int64}, ::Tuple{Symbol, Symbol})
Stacktrace:
 [1] top-level scope
   @ REPL[25]:1

julia> Iterators.product(1:2, (:a, :b)) |> collect
2×2 Matrix{Tuple{Int64, Symbol}}:
 (1, :a)  (1, :b)
 (2, :a)  (2, :b)

julia> Iterators.product([1 2; 3 4], (:a, :b)) |> collect
2×2×2 Array{Tuple{Int64, Symbol}, 3}:
[:, :, 1] =
 (1, :a)  (2, :a)
 (3, :a)  (4, :a)

[:, :, 2] =
 (1, :b)  (2, :b)
 (3, :b)  (4, :b)

I will check out the other packages shortly.

EDIT: LazyGrids does something else: it is a tuple of grids not a grid of tuples.
EDIT2: StructuredGrids promises the same but fails on the same edge cases and has less test coverage (I'll contact the author)

[noblock]

[aplavin]

See also:

• [WIP] ProductedArrays JuliaArrays/MappedArrays.jl#42
• https://github.com/JuliaData/SplitApplyCombine.jl#productviewf-a-b

All of these work with abstractarrays only, indeed - no tuples. Just wanted to point out prior art so that not to duplicate functionality unnecessarily.
Still, nothing wrong with creating a new thing if existing packages don't do what you need, and this cannot easily fit into their interface. That's why I made RectiGrids, for example: I need keyed/labeled arrays, an no other grid package focuses on that.

[noblock]