一、python入门
1、python的标准格式
创建python文件以.py结尾
如:vi hello.py
#!/usr/bin/env python
#-*- coding:utf-8 -*- #python3.5以上版本默认可以使用中文。
print "Hello Word"
执行:
python hello.py 即可
或者增加执行权限:chmod 755 hello.py
./hello.py
2、变量
name = "liudong"
name2 = name
然后把name = "liuyansheng"
#name2 不变,原因是一旦修改,重新创建。name2会重新开辟一块新内存空间。
集合就不同了:
name = ['liu','yan','sheng',]
name2 = name
#name2会变,原因是集合和字符串不同他的各个元素不是连续的,name增加一个元素不会开辟一块新的空间,name2就会跟着改变。
3、输入
name = raw_input("请输入用户名:")
#打印输出的内容
print name
输入密码时,如果想隐藏密码,需要利用getpass模块中的getpass方法,即:
#!/usr/bin/env python
#-*- coding: utf-8 -*-
#liudong
import getpass
#将用户输入的内容赋值给name变量
pwd = getpass.getpass("请输入密码:")
#打印输入的内容
print name
4、流程控制
(1)用户身份认证:
语法:if...else if...elif...elif...else
![](https://images.cnblogs.com/OutliningIndicators/ContractedBlock.gif)
#!/usr/bin/env python #-*- coding: utf-8 -*- #liudong import getpass name = raaw_input("请输入用户名:") pwd = raw_input("请输入密码:") if name =="liudong" and pwd =="123456": print "登陆成功" else: print "登陆失败"
(2)猜年龄:
![](https://images.cnblogs.com/OutliningIndicators/ContractedBlock.gif)
#!/usr/bin/env python #-*- coding: utf-8 -*- #liudong liudong = 24 guess_age = int(input("guess age:")) if guess_age == liudong: print ("yes") elif guess_age > liudong: print ("smaller....") else: print ("bigger....")
循环猜3次,猜对退出:
![](https://images.cnblogs.com/OutliningIndicators/ContractedBlock.gif)
#!/usr/bin/env python #-*- coding: utf-8 -*- #liudong liudong = 24 count = 0 while True: if count == 3: break guess_age = int(input("guess age:")) if guess_age == liudong: print ("yes") break elif guess_age > liudong: print ("smaller....") else: print ("bigger....") count +=1
最多循环猜3次,猜对自动退出,猜错提示“fuck off”:
![](https://images.cnblogs.com/OutliningIndicators/ContractedBlock.gif)
#!/usr/bin/env python #-*- coding: utf-8 -*- #liudong liudong = 24 count = 0 while count < 3 guess_age = int(input("guess age:")) if guess_age == liudong: print ("yes") break elif guess_age > liudong: print ("smaller....") else: print ("bigger....") count +=1 else: print ("fuck off")
注:continue 是跳出当前循环,break是跳出整个循环。
《用户登陆》-代码
https://www.processon.com/diagraming/57985ffde4b0bc50fa52a09b 用户登陆流程图
注:新建user_info.txt用户文件、和user_lock_info.txt文件。
完整代码如下:
#!/usr/bin/env/python import sys,os,getpass #os.system('clear') #清屏 i=0 while i < 3: #只要用户异常登录不超过3次,可以不断循环 name = input('\33[32m请输入用户名:\33[37m') lock_file = open('user_lock_info.txt','a+') #当用户输入用户名后,打开锁定文件 检查此用户是否已经lock掉了 lock_list = lock_file.readlines() #按行的形式打开 for lock_line in lock_list: #循环lock文件 lock_line =lock_line.strip('\n') #去掉换行符 if name == lock_line: #如果lock,直接退出 sys.exit('用户 %s 已经被锁定,退出!' % name) user_file = open('user_info.txt') #打开账号文件 user_list = user_file.readlines() for user_line in user_list: #对账号文件进行循环匹配 (user,password) = user_line.strip('\n').split() #分别获取账号、密码 if name == user: #如果用户名正常匹配 a = 0 while a < 3: #只要用户密码异常输入不超过3次就不断循环 passwd = input('\33[32m请输入密码:\33[37m') #输入密码,也可以做隐藏密码 if passwd == password: #密码正确匹配,提示欢迎登录 print('欢迎登陆管理平台,用户 %s !' % name) sys.exit(0) #正常退出,调用系统退出命令 else : if a != 2: #a=2时,是最后一次机会,不会提示0次机会了 print('用户 %s 密码错误,请重新输入,还有 %d 次机会' % (name,2 - a)) a += 1 #密码输错后,循环增加1 else: lock_file.write(name + '\n') #密码输错三次后,将该用户写入lock文件 sys.exit('用户 %s 达到最大登陆次数将被锁定退出' % name) else: if i != 2: #i=2时,是最后一次机会,不再提示0次机会了 print ('用户 %s 不存在,请重新输入,还有 %d 次机会' % (name,2 -i)) i += 1 #当用户输错时,循环增加1 else: print('用户 %s 不存在,退出!') #用户输入3次错误后,异常退出 lock_file.close() #关闭lock文件 user_file.close() #关闭账号、密码文件
《用户登陆》-代码
https://www.processon.com/diagraming/57986e66e4b0636f3aa4d175 三级菜单流程图
完整代码如下:
#!/usr/bin/env python #-*- encoding:utf8 -*- chinamap = { "山东省":{ "济南":["市中区1","历下区2","天桥区","槐荫区","历城区","长清区","章丘市","平阴县","济阳县","商河县","其他"], "青岛":["市南区","市北区","城阳区","四方区","李沧区","黄岛区","崂山区","胶南市","胶州市","平度市","莱西市","即墨市","其他"] }, "北京市":{ "北京":["东城区","西城区","崇文区","宣武区","朝阳区","海淀区","丰台区","石景山区","房山区","通州区","顺义区","昌平区","大兴区","怀柔区","平谷区","门头沟区","密云县","延庆县","其他"], }, "广东省":{ "广州":["越秀区","荔湾区","海珠区","天河区","白云区","黄埔区","番禺区","花都区","南沙区","萝岗区","增城市","从化市","其他"], "深圳":["福田区","罗湖区","南山区","宝安区","龙岗区","盐田区","其他"] } } flag = True try_sheng = 0 try_city = 0 try_area = 0 while flag: if try_sheng < 3 : print ('>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>') for sheng in chinamap.keys(): #获取变量的键 print (sheng) print ('============================================================') shengfen_input = input('请输入要查询的省份:') city_flag = True while city_flag: if try_city < 3 : if shengfen_input.strip() in chinamap: #执行下面的操作 print ('下面请输入城市信息') print ('============================================================') for city in chinamap[shengfen_input].keys(): print (city) print ('============================================================') city_input = input('请输入要查询的城市名称:') area_flag = True while area_flag: if try_area < 3 : if city_input.strip() in chinamap[shengfen_input]: print ('下面请输入城区信息') print ('============================================================') for city_area in chinamap[shengfen_input][city_input]: print (city_area) print ('============================================================') area_input = input('请输入要查询的区域信息:') if area_input.strip() in chinamap[shengfen_input][city_input]: print ('当前查询的是:',shengfen_input,city_input,area_input) flag = False city_flag = False break else: print ('没有要查询的区域,请重新输入') try_area += 1 else: print ("没有要查询的城市,请重新输入") try_city +=1 area_flag = False else: print ('三次操作错误,退出程序') flag = False city_flag = False area_flag = False else: print ("没有要查询的省份,请重新输入") try_sheng += 1 city_flag = False else: print ('三次操作错误,退出程序') flag = False city_flag = False else : print ('三次操作错误,退出程序') flag = False
作者: 东邪西毒
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