python笔记-0423

一、条件控制：

1、if语句

if-else

age = int(input("请输入年龄："))
if age >= 18:
    print("成年人")
else:
    print("未成年")
print("结束")

age = int(input("请输入年龄："))
if 18 <= age <= 65:
    print("合法工作年龄")
else:
    print("不合法")
print("结束")

if-elif-else

score = float(input("请输入成绩："))
if 90 <= score <= 100:
    print("优秀")
elif 80 <= score:
    print("良好")
elif 70 <= score:
    print("一般")
elif 60 <= score:
    print("及格")
else:
    print("不及格")
print("结束")


holiday = input("请输入节日：")
if holiday == "情人节":
    print("玫瑰")
elif holiday == "圣诞节":
    print("吃苹果")
elif holiday == "生日":
    print("吃蛋糕")
else:
    print("吃大餐")

2、if嵌套

ticlet = input("请出示你的车票：")
if ticket == "k51":
    length = float(input("请输入刀具长度："))
    if length >= 15:
        print("管制刀具，不能上车")
    else:
        print("可以上车")
else:
    print("没有车票，不能上车")


money = float(input("请输入总价："))
if money >= 500:
    vip = input("请输入vip等级：")
    if vip == "1":
        money = money * 0.8
    elif vip == "2":
        money = money - money % 10
    elif vip == "3":
        money = int(money)
else:
    sex = input("请输入性别：")
    if sex == "男":
        print("送皮带一条")
    else:
        print("送小包一个")
print("应付%.2f元"%money)

3、三元表达式：

a = 3
b = 4
c = a if a > b else b    #如果a>b，c = a，否则c = b
print(c)    #4

a = 3 
b = 4
c = 5
c +=  a if a > b else b    #如果a >b , c = c + a ,否则c = c + b
print(c)    #9

a = 3
b = 4
c = 5
c *= a if a > b else b    #如果a>b,c = c * a,否则c = c * b
print(c)    #20

a = 3
b = 4
c = 5
c += a + b if a > b else b    #如果a > b,c = c + (a + b),否则c = c + b
print(c)    #9

a = 4
b = 3
c = 5
c *= a +b if a >b else b    #如果a>b,c = c * (a +b),否则c = c * b
print(c)    #35

二、循环结构：

1、while循环：

while 循环3要素：
1、初始值
2、控制条件
3、步长

计算1-100的和：

i = 1
sum1 = 0
while i <= 100:
    sum1 += i
    i += 1
print(sum1)

计算1-100内，所有偶数的和，奇数的和，能被3整除的数的和：

i = 1
jsh = 0
osh = 0
zc3 = 0
while i <= 100:
    if i % 2 == 1:
        jsh += i
    else:
        osh += i
    if i % 3 == 0:
        zc3 += i
    i += 1
print("所有奇数和是：%d,所有偶数的和是：%d,所有能被3整除的数的和是：%d"%(jsh,osh,zc3))

求1 - 2 + 3 - 4 + 5…99的结果：

i = 1
x = 1
sum1 = 0
while i <= 99:
    sum1 = sum1 + x * i
    x *= -1
    i += 1
print(sum1)

i = 1
sum1 = 0
while i <= 99:
    if i % 2 == 1:
        sum1 += i
    else:
        sum1 -= i
print(sum1)

输入n个数，求平均值：

count1 = int(input("请输入需要统计个数字个数："))
sum1 = 0
i = 1
while i <= count1:
    num = float(input("请输入第%d个数："%i))
    sum1 += num
average = sum1 / count1
print("平均数是%f"%average)

输入n个数，求最大值:

count1 = int(input("请输入需要比较的个数："))
num1 = float(input("请输入第1个数："))
max = num1
i = 1
while i <= count1:
     num1 = float(input("请输入第%d个数："%(i + 1)))
     if num1 > max:
         max = num1
     i += 1
 print("最大值是：%f"%max"))

按要求用*输出直角三角形图形：

i = 1
while i <= 5:
    print("*" * i")
    i += 1

while-else:

i = i 
while i < 5:
    print(i)
    i+=1
else:    #当控制条件不成立时，执行else
    print(i,"程序走到这")
print("结束")

判断一个数是不是质数：

num1 = int(input("请输入一个正整数:"))
i = 2
while i < num1:
    if num1 % i == 0:
        print(i,"不是质数")
        break    #执行break后，跳出整个while-else循环
    i += 1
else:    #使用while-else可以减少判断次数
    print(i,"是质数")

num1 = int(input("请输入一个正整数："))
i = 2
while i < num1:
    if num1 % i == 0:
        print(i,"不是质数")
        break
    i += 1
if i == num1:    #多判断了一次
    print(i,"是质数")

循环次数 = 控制条件通过次数

i = 1
while 1 <= 10:
    if i % 4 == 0:
        break
    print(i)
    i += 1

i = 1
while i < 10:
    if i % 3 == 0 or i % 7 == 0 or i % 10 == 0:
        continue
    print(i)
    i += 1

2、for循环

遍历数字序列

for i in range(5,10,2):
    print(i)
else:
    print(i + 2,"不在范围内")

for i in range(15,10,-2):
    print(i)
else:
    print(i - 2,"不在范围内")

遍历字符串：

a = "12345"
for i in a:
    print(a)
else:
    print(i,"哈哈")

遍历元组：

a = (1,2,3,4,5)
for i in a:
    print(a)
else:
    print(i,"哈哈")

三、作业
1、用户登录模拟

while True:
    user_name = input("请输入用户名：")
    pass_word = input("请输入密码：")

    if user_name == "ouyangheng" and pass_word == "666":
        print("登录成功，欢迎使用")
        break
    else:
        print("密码错误，请重新输入!")

2、猜拳游戏 3局2胜

import random
count = 1
win = 0
lose = 0
while count <= 3:
    if win == 2 or lose == 2:
        break
    else:
        user = int(float(input("请出拳：0（剪刀），1（石头），2（布）:")))
        if user != 0 and user != 1 and user != 2:
            print("请重新输入正确数字")
            continue
        else:
            data = ["剪刀","石头","布"]
            com = random.randint(0,2)
            print("你出{}，电脑出{}".format(data[user],data[com]))
            if user == com:
                print("平局")
                continue
            elif user == 0 and com == 2 or user == 1 and com == 0 or user == 2 and com == 1:
                win += 1
                print("你赢了")
            else:
                lose += 1
                print("你输了")
                pass
    count += 1

3、数字炸弹：

import random,time
bomb = random.randint(1,100)
star = 1
end = 100

while True:
    num = int(input("请输入{}到{}之间的数字:".format(star,end)))
    if num == bomb:
        print("boom！你输了！")
        break
    elif num > bomb:
        print("大了")
        end = num - 1
    else:
        print("小了")
        star = num + 1

    print("请输入%d到%d之间的数字:"%(star,end))
    time.sleep(1)
    com = random.randint(star,end)
    print("电脑输入的数字是%d"%com)
    if com == bomb:
        print("boom!电脑输了！")
        break
    elif com > bomb:
        print("大了")
        end = com - 1
    else:
        print("小了")
        star = com + 1

print("数字炸弹是%d"%bomb)