python内置模块-random

print(random.randint(1,10)) 生成随机整数，下限必须小于上限
print(random.randrange(1,10)) 生成随机整数，参数为（[start],stop,[step]）

random.random()  生成0,1的随机浮点数

随机生成4位验证码:

 import random
 checkcode = ''
 for i in range(4):
     current =random.randrange(0,4)
     if current == 2:
         temp = chr(random.randint(65,90)) #大写字母
     elif current != 3:
         temp = chr(random.randint(97,122)) #小写字母
     else:
         temp = random.randint(0,9)
     checkcode += str(temp)
 print(checkcode)

验证码