Initialize an Empty Array of Tuples in Julia

Question

I can't figure out how to initialize an empty array of tuples. The manual says:

The type of a tuple of values is the tuple of types of values... Accordingly, a tuple of types can be used anywhere a type is expected.

Yet this does not work:

myarray = (Int64,Int64)[]

But this does:

Int64[]

It would seem a type is expected in front of the empty square brackets, but the tuple type doesn't work. This <type>[] syntax is the only way I can find to get an empty typed Array (other methods seem to produce a bunch of #undef values). Is the only way to do it, and if it is, how can I type the Array with tuples?

BTW, my use case is creating an array of initially indeterminate length and pushing tuples onto it in a loop.

Answer 1

For people who look for the latest solution,

Tuple{Int, Int}[] works in v0.4

Also the verbose way Array{Tuple{Int, Int}}(0) works in v0.4 as well.

It creates a 0-element Array{Tuple{Int64,Int64},1}

Note that in v1.0 you'd need to write

Array{Tuple{Int, Int}}(undef, 0)

Answer 2

You can do Array((Int,Int),0) for this. It is probably feasible to add methods to getindex to make (Int,Int)[] work, but I'm not sure it's worth it. Feel free to open an issue.