DNA strand reverse

dnaRev.lua

function strandComplRev(s)
    local complements =
    {
        A = "T",
        T = "A",
        C = "G",
        G = "C",
    }

    local s2 = ""
    for c in string.gmatch(s, ".") do
        s2 = complements[c] .. s2
    end

    return s2
end