python的分支结构和循环结构

来源：互联网发布：数据抓取工具编辑：程序博客网时间：2024/05/17 06:30

if判断操作：

# Author:danchengimport getpass_username = "dancheng"_password = "123"username = input("username:");password = input("password:");if _username == username and _password == password:    print("登陆成功")else:    print("不符合")

效果图：

另一个案例：

# Author:danchengage_of_dancheng = 20guess_age = int(input("guess_age:"))if guess_age == age_of_dancheng:    print("对了")elif guess_age > age_of_dancheng:    print("猜大了")else:    print("猜小了");

while循环：

count = 0while True:    print("count:", count)    count = count + 1

实例：

# Author:danchengage_of_dancheng = 20count = 0while count < 3:    guess_age = int(input("guess_age:"))    if guess_age == age_of_dancheng :        print("对了")        break    elif guess_age > age_of_dancheng :        print("猜大了")    else:        print("猜小了");    count += 1if count == 3:    print("超过3次了")

for循环结构：

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

for i in range(0, 10, 3) : //0~10，步长3    print("loop ", i)

效果图：

loop 0

loop 3

loop 6

loop 9

实例:

# Author:danchengage_of_dancheng = 20count = 0for i in range(3) :    guess_age = int(input("guess_age:"))    if guess_age == age_of_dancheng :        print("对了")        break    elif guess_age > age_of_dancheng :        print("猜大了")    else:        print("猜小了");    count += 1else:    print("超过3次了")

continue:

for i in range(0, 10) :    if i < 5:        print("loop ", i)    else:        continueprint("hehe")

三元运算符:

d = a if a < b else c 找出a, b, c三个变量中的最小值

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