http://jingyan.baidu.com/article/b7001fe190ebf90e7382dd45.html
function random(n, m)
math.randomseed(os.clock()*math.random(1000000,90000000)+math.random(1000000,90000000))
return math.random(n, m)
end
function randomNumber(len)
local rt = ""
for i=1,len,1 do
if i == 1 then
rt = rt..random(1,9)
else
rt = rt..random(0,9)
end
end
return rt
end
function randomLetter(len)
local rt = ""
for i = 1, len, 1 do
rt = rt..string.char(random(97,122))
end
return rt
end
for i = 1, 5 do
print(randomLetter(7))
end