Find Max or Min

In Julia, it's most efficient to use the available functions maximum and minimum,

@show maximum([1,5,90,-2,213,2])
> maximum([1, 5, 90, -2, 213, 2]) = 213

@show minimum([1,5,90,-2,213,2])
> minimum([1, 5, 90, -2, 213, 2]) = -2

But sometimes, we need a slightly customized version, so here's how it's done in \(O(n)\).

function mymax(ary)
    largest = (nothing, nothing)
    for (k, el) in enumerate(ary)
        if isnothing(largest[1]) || largest[2] < el
            largest = (k, el)
        end
    end
    return largest
end