python3判断循环小练习

Posted 2020-09-21

1、使用while循环输出1 2 3 4 5 6 8 9 10

i = 1
while i <= 10:
    if i == 7:
        i += 1
        print(end=‘  ‘)
        continue
    print(i, end=‘ ‘)
    i += 1

　　

2、求1-100的所有数的和

s = 0
for i in range(1, 101):
    s = s + i
    i += 1
print(s)

　　

3、输出 1-100 内的所有奇数

for i in range(1, 100):
    if i % 2 == 1:
        print(i, end=‘ ‘)
    i += 1

　　

4、输出 1-100 内的所有偶数

for i in range(1, 101):
    if i % 2 == 0:
        print(i, end=‘ ‘)
    i += 1

　　

5、求1-2+3-4+5 ... 99的所有数的和

s = 0
for i in range(1, 100):
    if i % 2 == 1:
        s = s + i
    elif i % 2 == 0:
        s = s - i
    i += 1
print(s)

　　

6、用户登陆（三次机会重试）

name = ‘egon‘
passwd = ‘123‘
i = 1
while i <= 3:
    na = input(‘请输入用户名：‘)
    pa = input(‘请输入密码：‘)
    if na == name and pa == passwd:
        print(‘登录成功！‘)
        break
    elif na == name and pa != passwd:
        print(‘密码错误，还有‘, 3 - i, ‘次机会‘)
    else:
        print(‘无此用户，还有‘, 3 - i, ‘次机会‘)
    i += 1

　　

7、九九乘法表

for i in range(1, 10):
    for j in range(1, i+1):
        print(‘%s*%s*=%s‘ % (i, j, i*j), end=‘ ‘)
    print(‘\n‘)

　　

8、判断登录，按q退出

tag = True
while tag:
    name = input(‘your name:‘)
    password = input(‘your password:‘)
    if name == ‘egon‘ and password == ‘123‘:
        print(‘login successful‘)
        while tag:
            res = input(‘cmd>> ‘)
            if res == ‘q‘:
                tag = False
                continue
            print(‘用户命令是%‘ % res)