Nested list comprehensions in Julia

Question

In python I can do nested list comprehensions, for instance I can flatten the following array thus:

a = [[1,2,3],[4,5,6]]
[i for arr in a for i in arr]
         


        

Answer 1

You can get some mileage out of using the splat operator with the array constructor here (transposing to save space)

julia> a = ([1,2,3],[4,5,6],[7,8,9])
([1,2,3],[4,5,6],[7,8,9])

julia> [a...]'
1x9 Array{Int64,2}:
 1  2  3  4  5  6  7  8  9