lua 通用函数

function tomoney(num)
nums = tostring(num)
local out = ""
local j = 1
for i = string.len(nums)  , 1 ,-1   do
local sc = string.byte(nums , i)
out = out..string.char(sc)
if (j%3 == 0 and i ~=1) then
out = out..","
end
j = j +1
end
out = string.reverse(out)
return out
end