Julia: append to an empty vector
I am somewhat new to Julia and came across this question after getting a similar error. To answer the original question for Julia version 1.2.0, all that is missing are ()
:
x = Vector{Float64}()
append!(x, rand(10))
This solution (unlike x=zeros(0)
) works for other data types, too. For example, to create an empty vector to store dictionaries use:
d = Vector{Dict}()
push!(d, Dict("a"=>1, "b"=>2))
A note regarding use of push!
and append!
:
According to the Julia help, push!
is used to add individual items to a collection, while append!
adds an collection of items to a collection. So, the following pieces of code create the same array:
Push individual items:
a = Vector{Float64}()
push!(a, 1.0)
push!(a, 2.0)
Append items contained in an array:
a = Vector{Float64}()
append!(a, [1.0, 2.0])
Your variable x
does not contain an array but a type.
x = Vector{Float64}
typeof(x) # DataType
You can create an array as Array(Float64, n)
(but beware, it is uninitialized: it contains arbitrary values) or zeros(Float64, n)
,
where n
is the desired size.
Since Float64
is the default, we can leave it out.
Your example becomes:
x = zeros(0)
append!( x, rand(10) )