Obtaining the last element of a ProductIterator

General Usage
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2

In a future version (1.6?) the following works:

julia> it = Iterators.product(1:3, 2:3)
Base.Iterators.ProductIterator{Tuple{UnitRange{Int64}, UnitRange{Int64}}}((1:3, 2:3))

julia> last(it, 1)
1-element Vector{Tuple{Int64, Int64}}:
 (3, 3)

This was added in https://github.com/JuliaLang/julia/pull/34868

This works as long as the iterator implements reverse. There was recently a discussion here about the difficulties of adding a generic last method: Getting the last element of an iterator. I planned to submit a PR but as explained in that thread I couldn’t find an implementation that was performant and backward-compatible.

As a workaround @mschauer suggested foldl((_, y) -> y, itr), which also works fine here:

julia> foldl((_,y)->y, Iterators.product(1:3, 2:3))
(3, 3)
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