Julia from the perspective of a pythonista

[stevengj]

@Jake

Yesterday I was experimenting with passing an array to a function using the most general Type possible. I finally decided that because arrays are passed by pointer, that they need to be very specific when passed to a function.

Probably you are confused about invariance, e.g. you should have declared a parameter as AbstractVector{<:Real} but you declared it as AbstractVector{Real} instead — the former allows Vector{Float64} and the latter does not. This comes up a lot in the forums, e.g. here and here and here and here etcetera.