Multidimensional Array Comprehension in Julia

Question

I\'m mucking about with Julia and can\'t seem to get multidimensional array comprehensions to work. I\'m using a nightly build of 0.20-pre for OSX; this could conceivably be

Answer 1

I think you are just reading the list comprehension wrong

julia> [x+5y for  x in 1:5, y in 0:1]
5x2 Array{Int64,2}:
 1   6
 2   7
 3   8
 4   9
 5  10

When you use them in multiple dimensions you get two variables and need a function for the cell values based on the coordinates

For your second question I think that you should reconsider your requirements. Julia uses typed arrays for performance and storing different types in different columns is possible. To get an untyped array you can use {} instead of [], but I think the better solution is to have an array of tuples (Int, Bool) or even better just use two arrays (one for the ints and one for the bool).

julia> [(i,false) for i in 1:5]
5-element Array{(Int64,Bool),1}:
 (1,false)
 (2,false)
 (3,false)
 (4,false)
 (5,false)