How to define a Julia Vector with only integers ≥ 0

General Usage
, ,
1

As input for a function, I need a Vector with values greater than or equal to zero.

I tried l = Array{>:UInt8, 1}

However push!(l, 9) throws an error.
MethodError: no method matching push!(::Type{Vector{>:UInt8}}, ::Int64)

What is the right way to define such an array?

Use case:

function concatenate_integers(l::Array{Int, 1})
    """
    concatenate_numbers([3, 4, 5]) == 345
    """
    @assert all(i -> i ∈ 0:9, l) "Only integers in range 0:9 are valid"
    s = 0 # sum
    for (i, n) in enumerate(reverse(l))
        s += n * 10^(i-1)
    end
    return s
end

I would like to replace the all(i -> i ∈ 0:9, l) part by enforcing the right input type.

2

It’s because 1 is an Int and not a UInt

julia> a = UInt[]
UInt64[]

julia> push!(a, UInt(1))
1-element Vector{UInt64}:
 0x0000000000000001
4

UInt8
smallest value = 0
largest value = 255

make sure you are HAPPY with the limitations.

5

If you really want to do this by relying on the type system, my package TypeDomainNaturalNumbers.jl is the solution. However it’s not clear whether this would fit your, unknown, use case.