20180805：写出一个，数字和字母的随机密码

import string
import random
letters_num= random.randint(1,8)
numbers_num = 9-letters_num
pass_wd = " "

for i in range(9):
    if random.randint(0,1):#0和1随机获取，1获取字母，0获取数字
        pass_wd+=string.ascii_letters[random.randint(0,52)]
    else:    
        pass_wd+="0123456789"[random.randint(0,9)]

print (pass_wd)