Comment by markkitti

The 0 or 1 based indexing is actually a very superficial debate for people not very familiar with Julia. Note that 1-based indexing is a standard library feature not inherent to the Julia language itself.

The real indexing issue is whether arbitrary-base abstraction is too easily available.

    # Correct, Vector is 1-based
    function mysum(v::Vector{T}) where {T <: Integer}
        s = zero(T)
        for i in 1:length(v)
            s += v[i]
        end
        return s
    end

    #Incorrect, AbstractVector is not necessarily one based
    function mysum(v::AbstractVector{T}) where {T <: Integer)
        s = zero(T)
        for i in 1:length(v)
            s += v[i]
        end
        return s
    end

    #Correct
    function mysum(v::AbstractVector{T}) where {T <: Integer)
        s = zero(T)
        for e in v
            s += e
        end
        return s
    end

Basically, the concrete `Vector` type is 1-based. However, `AbstractVector` is could have an arbitrary first index. OffsetArrays.jl is a non-standard package that provides the ability to create arrays with indexes that can start at an arbitrary point including 0.