Loop-Created Matrices in Julia

Question

Let's say we have arrays u and v, and function f. We want a matrix F consisting of f(ui, vi) for all members of u and v. Trying this:

F = [ [f(ui,vi) for vi in v] for ui in u]

The result is an array of arrays (In Julia's words, Array{Array{Int64,1},1})

How can I reshape this into a 2-dimensional array? (Array{Int64,2})

Answer 1

Instead of two nested comprehensions, just use one multidimensional comprehension:

F = [f(ui,vi) for vi in v, ui in u]