1. 纯数字验证码（4位）
import random
verificationcode = ‘‘
for i in range(4):
current = random.randint(0,9)
verificationcode+=str(current)
print(verificationcode)
2. 数字字母混合验证码（4位）
import random
verificationcode = ‘‘
for i in range(4):
current = random.randint(0,4)
if current == i:
t_code = chr(random.randint(65,90)) #chr将数字转换为ascii码中的字母
else:
t_code = random.randint(0,9)
verificationcode+=str(t_code)
print(verificationcode)
原文：http://www.cnblogs.com/cnwangshijun/p/7374591.html