生成随机数或随机字母

#生成四位随机数
import random
a = ""
for i in range(0,4):
    i = random.randint(1,9)
    a = a+str(i)
print(a)

#随机生成四位字母加数字
import random
a = ""
for i in range(0,4):
    b = random.randint(0,4)
    if i == b:
        c = random.randint(1,9)
        a = a+str(c)
    else:
        c = chr(random.randint(65,90))
        a = a + str(c)
print(a)

 
  chr(random.randint(65,90))#随机选取一个大写字母 
  chr(random.randint(97,122))#随机选取一个小写字母 
  random.choice([chr(random.randint(65,90)),chr(random.randint(97,122))])