Iterator flatten with nested tuples

New to Julia
1

I am trying to flatten the following Iterator:

julia> it=Iterators.product(1:3,1:4); collect(it)
3×4 Matrix{Tuple{Int64, Int64}}:
 (1, 1)  (1, 2)  (1, 3)  (1, 4)
 (2, 1)  (2, 2)  (2, 3)  (2, 4)
 (3, 1)  (3, 2)  (3, 3)  (3, 4)

and hope to get an length 12 iterator that yields a pair of indices a time. However, Iterators.flatten(it) returns a length 24 iterator that yields one index a time:

julia> collect(Iterators.flatten(it))
24-element Vector{Int64}:
 1
 1
 2
...

So how to generate the effect of two indices at a time? I’m looking for an iterator that yields these pairs.

3

If you don’t need the product, maybe this is what you can use:

julia> it = ( (i,j) for j in 1:4 for i in 1:3 )
Base.Iterators.Flatten{Base.Generator{UnitRange{Int64}, var"#22#23"}}(Base.Generator{UnitRange{Int64}, var"#22#23"}(var"#22#23"(), 1:4))

julia> collect(it)
12-element Vector{Tuple{Int64, Int64}}:
 (1, 1)
 (2, 1)
 (3, 1)
 (1, 2)
 (2, 2)
 (3, 2)
 (1, 3)
 (2, 3)
 (3, 3)
 (1, 4)
 (2, 4)
 (3, 4)
4

Did not realize the extra for instead of a , to have a flattening effect. Thank you!

5

Another way is to shield it inside Ref() or in a tuple:

collect(Iterators.flatten((it,)))
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