lua四舍五入

RT.

local math = require('math')

function roundOff(num, n)
    if n > 0 then
        local scale = math.pow(10, n-1)
        return math.floor(num / scale + 0.5) * scale
    elseif n < 0 then
        local scale = math.pow(10, n)
        return math.floor(num / scale + 0.5) * scale
    elseif n == 0 then
        return num
    end
end