《python编程：从入门到实践》答案（第十章）

第十章

with open("learning_python.txt") as file_object:
	contents=file_object.read()
	print(contents)

with open("learning_python.txt") as file_object:
	for line in file_object:
		print(line.rstrip())

contents=''
with open("learning_python.txt") as file_object:
	lines=file_object.readlines()
for line in lines:
	print(line.rstrip())

contents=''
with open("learning_python.txt") as file_object:
	lines=file_object.readlines()
for line in lines:
	line=line.replace('python','C')
	print(line.rstrip())

 

name=input("Please enter your name: ")
file_name='guest.txt'
with open(file_name,'a') as file_object:
	file_object.write(name+"\n")
with open(file_name) as need_read:
	lines=need_read.readlines()

file_name='guest.txt'
while(True):
	name=input("Please enter your name: ")
	if name!='quit':
		with open(file_name,'a') as file_object:
			file_object.write(name+"\n")
	else:
		break

file_name='reason.txt'
while(True):
	reason=input("Why you love programming ? ")
	if reason!='quit':
		with open(file_name,'a') as file_object:
			file_object.write(reason+'\n')
	else:
		break

with open(file_name) as need_r:
	lines=need_r.readlines()
for line in lines:
	print(line.rstrip())

try:
	num_1=input("Please enter the first number: ")
	x=int(num_1)
		
	num_2=input("Please enter the second number: ")
	y=int(num_2)
except ValueError:
	print("your input is not a number,try again.")
else:
	print(x+y)

print("Please enter two numbers.\n")
print("Enter 'q' to quit.")
while True:
	try:
		num_1=input("Please enter the first number: ")
		if num_1=='q':
			break
		x=int(num_1)
		
		num_2=input("Please enter the second number: ")
		if num_2=='q':
			break
		y=int(num_2)
	except ValueError:
		print("your input is not a number,try again.")
	else:
		print(x+y)

file_name='dogs.txt'
try:
	with open(file_name) as f:
		contents=f.read()
except FileNotFoundError:
	print("Tis file does not exist.")
else:
		print(contents)

file_name='dogs.txt'
try:
	with open(file_name) as f:
		contents=f.read()
except FileNotFoundError:
	pass
else:
		print(contents)

try:
	with open('alice.txt') as f:
		contents=f.read()
except FileNotFoundError:
	print("sorry ,this file does not exit.")
else:
	words_num=contents.lower().count('the')
	print(words_num)

import json
fav_num=input("Enter your favorite number: ")
file_name="favnum.json"
with open(file_name,'w') as f:
	json.dump(fav_num,f)
with open(file_name) as f:
	num=json.load(f)
	print("I know your favorite number! It's "+num+".")

import json

def get_favnum():
	file_name="favnum.json"
	try:
		with open(file_name) as f:
			num=json.load(f)
	except FileNotFoundError:
		return None
	else:
		return num
def print_favnum():
	num=get_favnum()
	if num:	
		print("I know your favorite number! It's "+num+".")
	else:
		file_name="favnum.json"
		num=input("Enter your favorite number: ")
		with open(file_name,'w') as f:
			json.dump(num,f)
print_favnum()

import json

def get_sorted_user():
	'''获取存储的用户名'''
	file_name="username.json"
	try:
		with open(file_name) as f:
			user_name=json.load(f)
	except FileNotFoundError:
		return None
	else:
		return user_name

def get_new_user():
	'''获取新的用户名'''
	user_name=input("Enter your name: ")
	file_name="username.json"
	with open(file_name,'w') as f:
		json.dump(user_name,f)
	return user_name

def greet():
	'''问候用户并指出名字'''
	user=get_sorted_user()
	if user:
		print("Welcome "+user+"~")
		ask=input("Am I right? Enter 'y' or 'no': ")
		if ask=='y':
			pass
		elif ask=='n':
			user=get_new_user()
			print("Welcome "+user+"~")
	else:
		user=get_new_user()
		print("Welcome "+user+"~")
greet()