python-for循环

for i in range(10):
    print("loop",i)

i是临时变量，其实是for i in（0，1，2，3，4，5，6，7，8，9）

for-else

age_of_oldboy = 56
for i in range(3):
    guess_age = int(input("guess_age:"))
    if guess_age == age_of_oldboy:
        print("yes,you got it.")
        break
    elif guess_age > age_of_oldboy:
        print("think smaller...")
    else:
        print("think bigger!")
else:
    print("you have tried too many times...!")

for下面的正常走完，才走else，不是正常走完，不走else

for i in range(0,10,2):
    print("loop",i)

2是每隔一个跳一个，相当于步长，默认1

age_of_oldboy = 56
count = 0
while count < 3:
    guess_age = int(input("guess_age:"))
    if guess_age == age_of_oldboy:
        print("yes,you got it.")
        break
    elif guess_age > age_of_oldboy:
        print("think smaller...")
    else:
        print("think bigger!")
        count += 1
    if count == 3:
        countine_confirm = input("do you want to keep guessing...?")
        if countine_confirm != 'n':
            count = 0
else:
    print("you have tried too many times...!")