if elif else

• if  else

格式    

if xxx:
    print()
else:
    print()

age_of_oldboy = 56

guess_age = int(input("age:"))#age是整数，所以 需要将字符转换为整型

if guess_age == age_of_oldboy:
    print("you are right")

else:
    print("think bigger")

• if elif else

格式：

if xxx:
    print()
elif xxx:
    print()
else:
    print()

age_of_oldboy = 56

guess_age = int(input("age:"))#age是整数，所以 需要将字符转换为整型

if guess_age == age_of_oldboy:
    print("you are right")
elif guess_age > age_of_oldboy:
    print("think small")
else:
    print("think bigger")