Python练习题（基础知识练习题（一））

#!/usr/bin/env python
#-*- encoding:utf-8 -*-

n = 1
while n <= 10:
   if n == 7:
      pass #换成continue不行,因为会跳过本次循环,n不能+1,n永远==7,永远跳过本次循环。
   else:
      print(n)
   n += 1
   # print(‘wss‘,n)

#!/usr/bin/env python
#-*- encoding:utf-8 -*-

n = 0
while n <= 9:
    n += 1
    if n == 7:
        pass # 换成continue可以，因为虽然跳出了本次循环，但是下次循环的时候n可以+1
    else:
        print(n)

#!/usr/bin/env python
#-*- encoding:utf-8 -*-

n = 0;s = 0 #s是之前所有数的总和
while n <= 99:
    n += 1
    s += n
    # print(s) #输出每次循环的总和
print(s) #输出最后的总和

#!/usr/bin/env python
#-*- encoding:utf-8 -*-

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

#!/usr/bin/env python
#-*- encoding:utf-8 -*-

n = 0
while n <= 99:
    n += 1
    if n % 2 == 1:
        print(n)

#!/usr/bin/env python
#-*- encoding:utf-8 -*-

for n in range(1,101,2):
        print(n)

#!/usr/bin/env python
#-*- encoding:utf-8 -*-

n = 0
while n <= 99:
    n += 1
    if n % 2 == 0:
        print(n)

#!/usr/bin/env python
#-*- encoding:utf-8 -*-

for n in range(2,101,2):
        print(n)

#!/usr/bin/env python
#-*- encoding:utf-8 -*-

n = 0;s = 0
while n <= 98:
    n += 1
    if n % 2 == 0:
        s -= n
    else:
        s += n
    # print(s) #输出每次循环运算的结果
print(s) #输出最后的运算结果

#!/usr/bin/env python
#-*- encoding:utf-8 -*-

s = 0
for n in range(1,100):
        # print(n)
        if n % 2 == 0:
            s -= n
        else:
            s += n
print(s)

#!/usr/bin/env python
# -*- encoding: utf8 -*-

import getpass

count = 0
while count < 3:
    user = input(‘请输入用户名:‘)
    pwd = getpass.getpass(‘请输入密码:‘)
    if user == ‘wss‘ and pwd == ‘123‘:
        print(‘欢迎登陆‘)
        print(‘..........‘)
        break
    else:
        print(‘用户名或者密码错误‘)
    count += 1

#!/usr/bin/env python
#-*- encoding:utf-8 -*-

import getpass
username = ‘wss‘
password = ‘123‘
flag = 0
def login():
    user = input(‘username:‘)
    passwd = getpass.getpass(‘password:‘)
    return user,password
while flag<3:
    user,passwd = login()
    if username == user and password == passwd:
        print(‘hello,jason‘)
        break
    else:
        flag += 1
        print (‘error,input again‘)