Python百例-11~20

11-条件表达式、三元运算符

a = 10
b = 20

if a < b:
    smaller = a
else:
    smaller = b

print(smaller)

s = a if a < b else b  # 和上面的if-else语句等价

print(s)

12-判断练习：用户名和密码是否正确

import getpass  # 导入模块

username = input('username: ')
# getpass模块中，有一个方法也叫getpass
password = getpass.getpass('password: ')

if username == 'bob' and password == '123456':
    print('Login successful')
else:
    print('Login incorrect')

13-猜数：基础实现

import random

num = random.randint(1, 10) # 随机生成1－10之间的数字
answer = int(input('guess a number: '))  # 将用户输入的字符转成整数
if answer > num:
    print('猜大了')
elif answer < num:
    print('猜小了')
else:
    print('猜对了')

print('the number:', num)

14-成绩分类1

score = int(input('分数: '))

if score >= 90:
    print('优秀')
elif score >= 80:
    print('好')
elif score >= 70:
    print('良')
elif score >= 60:
    print('及格')
else:
    print('你要努力了')

15-成绩分类2

score = int(input('分数: '))

if score >= 60 and score < 70:
    print('及格')
elif 70 <= score < 80:
    print('良')
elif 80 <= score < 90:
    print('好')
elif score >= 90:
    print('优秀')
else:
    print('你要努力了')

16-石头剪刀布

import random

all_choices = ['石头', '剪刀', '布']
computer = random.choice(all_choices)
player = input('请出拳: ')

# print('Your choice:', player, "Computer's choice:", computer)
print("Your choice: %s, Computer's choice: %s" % (player, computer))
if player == '石头':
    if computer == '石头':
        print('平局')
    elif computer == '剪刀':
        print('You WIN!!!')
    else:
        print('You LOSE!!!')
elif player == '剪刀':
    if computer == '石头':
        print('You LOSE!!!')
    elif computer == '剪刀':
        print('平局')
    else:
        print('You WIN!!!')
else:
    if computer == '石头':
        print('You WIN!!!')
    elif computer == '剪刀':
        print('You LOSE!!!')
    else:
        print('平局')

17-改进的石头剪刀布

import random

all_choices = ['石头', '剪刀', '布']
win_list = [['石头', '剪刀'], ['剪刀', '布'], ['布', '石头']]
prompt = """(0) 石头
(1) 剪刀
(2) 布
请选择(0/1/2): """
computer = random.choice(all_choices)
ind = int(input(prompt))
player = all_choices[ind]

print("Your choice: %s, Computer's choice: %s" % (player, computer))
if player == computer:
    print('\033[32;1m平局\033[0m')
elif [player, computer] in win_list:
    print('\033[31;1mYou WIN!!!\033[0m')
else:
    print('\033[31;1mYou LOSE!!!\033[0m')

18-猜数，直到猜对

import random

num = random.randint(1, 10)
running = True

while running:
    answer = int(input('guess the number: '))
    if answer > num:
        print('猜大了')
    elif answer < num:
        print('猜小了')
    else:
        print('猜对了')
        running = False

19-猜数，5次机会

import random

num = random.randint(1, 10)
counter = 0

while counter < 5:
    answer = int(input('guess the number: '))
    if answer > num:
        print('猜大了')
    elif answer < num:
        print('猜小了')
    else:
        print('猜对了')
        break
    counter += 1
else:  # 循环被break就不执行了，没有被break才执行
    print('the number is:', num)

20-while循环，累加至100

sum100 = 0
counter = 1

while counter < 101:
    sum100 += counter
    counter += 1

print(sum100)
#因为循环次数是已知的，实际使用时，建议用for循环