生成隨機數或隨機字母

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

#隨機生成四位字母加數字
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))#隨機選取一個大寫字母 
          chr(random.randint(97,122))#隨機選取一個小寫字母 
          random.choice([chr(random.randint(65,90)),chr(random.randint(97,122))])