import random
import string
import os
#第一种方法
seed ="1234567890abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ!@#$%^&*()_+=-"
sa =[]
for i in range(8):
sa.append(random.choice(seed))
salt = ''.join(sa)
print salt

#第二种方法
salt =''.join(random.sample(string.ascii_letters+string.digits,8))
print salt
#第三种方法(不适用与python3.x)
temp = ''.join(map(lambda xx:(hex(ord(xx))[2:]),os.urandom(3)))
print temp