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

Don't have enough reputation for comment so posting a modification @ben-hammer. Thanks for the example of flatten(), it was helpful to me.

But it did break if the tuples/arrays contained strings. Since strings are iterables the function would further break them down to characters. I had to insert condition to check for ASCIIString to fix that. The code is below

    function flatten(x, y)
        state = start(x)
        if state==false
            push!(y, x)
        else
            if typeof(x) <: String
                push!(y, x)
            else 
                while (!done(x, state)) 
                    (item, state) = next(x, state) 
                    flatten(item, y)
                end
            end
        end
        y
    end
    flatten(x)=flatten(x,Array(Any, 0))