Python:从入门到实践--第十章--文件和异常--练习
#1.python学习笔记:在文本编辑器中新创建一个文件,写几句话老总结你至此学到的python知识 #其中‘In Python you can’ 打头。将这个文件命名为learning_python.txt.并将其存储到为本章学习目录下 #编写一个程序,它读取这个文件,并将你序偶写的内容打印三次:第一次打印时读取整个文件 #第二次打印时遍历文件对象,第三次打印时将各行存储在一个列表中,再在with代码块外打印它们 with open('learning_python.txt') as file_object: contents = file_object.read() print(contents) filename = 'learning_python.txt' with open(filename) as file_object1: for line in file_object1: print(line.rstrip()) print('\n') with open(filename) as file_object2: lines = file_object2.readlines() for line in lines: print(line.rstrip()) print('\n') #2.在1中完成的基础上,使用方法replace()将learning_python.txt中的Python替换成其它任意一门语言 filename = 'learning_python.txt' with open(filename) as file_object1: for line in file_object1: line = line.replace('Python','Java') print(line.rstrip()) #1.访客:编写一个程序,提示用户输入其名字;用户作出响应后,将其名字写入到文件guest.txt中 guest_names = input("Enter your name: ") with open('guest.txt','a') as file_object: file_object.write(guest_names + '\n') #2.访问名单:编写一个while循环,提示用户输入其名字。用户输入其名字后,在屏幕打印一句问候语 #并将一条访问记录添加到文件guest_book.txt中。确保这个文件中的每条记录都独占一行 while True: print("Enter a to quit.") names = input("Enter your name: ") if names == 'q': break messages = "Hello! " + names print(messages) with open('guest_book.txt','a') as file_object: file_object.write(messages + '\n') #3.关于编程的调查:编写一个while循环,询问用户为何喜欢编程。每当用户输入一个原因后, #都将其添加到一个存储所有原因的文件中 while True: print("Enter q to quit.") reasons = input("Why do you like programming? ") if reasons == 'q': break with open('reason_books.txt','a') as file_object: file_object.write(reasons + '\n') #1.加法运算:提示用户提供数值输入时,常出现的一个问题是,用户提供的是文本而不是数字 #在这种情况下,当你尝试将输入转换为整数时,将引发TypeError异常。 #编写一个程序,提示用户输入两个数字,再将它们相加并打印结果。在用户输入的任一个值不是 #数字时都铺获TypeError异常,并打印一条友好的错误消息。 while True: try: first_number = int(input("Enter to the first number: ")) second_number = int(input("Enter to the second number: ")) sum = first_number + second_number except ValueError: print("Sorry,TypeError! please input again." else: print("The add result of two numbers:",sum) #2.猫和狗:创建两个文件cat.txt和dog.txt,在第一个文件中至少存储三只猫的名字 #在第二个文件中至少存储三条狗的名字。编写一个程序,尝试读取这些文件, #并将其内容打印到屏幕上。将这些代码放在一个try-except代码块中,以便文件 #不存在是捕获FileNotFound错误,并打印一条友好的消息,将其中一个文件移到另一个 #地方,并确认except代码块中的代码将正确执行。 def Openfile(filename): try: with open(filename) as file_read: contents = file_read.read() print(contents.rstrip()) except FileNotFoundError: print("Sorry,The file " + filename + " does not exit!") filename = 'alice.txt' Openfile(filename) filename ='dog.txt' Openfile(filename) #3.修改在2中所编写的except代码块,让程序不存在时一言不发 def Openfile(filename): try: with open(filename) as file_read: contents = file_read.read() print(contents.rstrip()) except FileNotFoundError: pass filename = 'alice.txt' Openfile(filename) filename ='dog.txt' Openfile(filename) #4.常见单词:找一些你想分析的图书,使用方法count()来确定特定单词或短语在字符串中出现的次数 def Ludong(filename): try: with open(filename) as file_object: contents = file_object.read() print(contents.rstrip()) print("The word appears " + str(contents.lower().count('ludong')) + " times.") except FileNotFoundError: print("The file " + filename + " does not exit!") filename = 'ludong.txt' Ludong(filename) #1.喜欢的数字:编写一个程序,提示用户输入他喜欢的数字,并使用 #json.dump()将这个数字存储到文件中。再编写一个程序,从文件中读取这个值 #并打“I know your favorite number! It's 。。 import json def StoreNumber(): #如果存储数字就获取它 filename = 'usernumber.json' try: with open(filename) as f_obj: usernumber = json.load(f_obj) except FileNotFoundError: return None else: return usernumber def get_new_number(): #提示用户输入数字 usernumber = input("Enter to your favorite number: ") filename = 'usernumber.json' with open(filename,'w') as f_obj: json.dump(usernumber,f_obj) return usernumber def ReadNumber(): #读取数字 usernumber = StoreNumber() if usernumber: print("I Know your favorite number! It's " + str(usernumber)) else: usernumber = get_new_number() print("I'll remember the number: " + str(usernumber)) ReadNumber() #2.验证用户:最后一个remember_me.py版本假设用户要么已输入其用户名,要么是首次运行改程序。 #我们应修改这个程序,应对这样的情形:当前和最后一次运行该程序的用户并非同一个人 #因此,在greet_user()中打印欢迎用户回来的消息前,先询问用户名是否是对的 #如果不对,就调用get_new_username()让用户输入正确的用户名 import json def get_stored_username(): #如果存储了用户名就获取它 filename = 'username.json' try: with open(filename) as f_obj: username = json.load(f_obj) except FileNotFoundError: return None else: return username def get_new_user(): #提示用户输入名字 username = input("What's your name? ") filename = 'username.json' with open(filename,'w') as f_obj: json.dump(username,f_obj) return username def greet_user(): #问候用户 username = get_stored_username() if username: ask = "Your username is " + username +"?"+ "if not,please input N, " ask += "if yes,input Y: " ask_msg = input(ask) if ask_msg == 'Y': print("Welcome back," + username + '!') else: username = get_new_user() print("We'll remember you when you come back, " + username + '!') else: username = get_new_user() print("We'll remember you when you come back, " + username + '!') greet_user()