python练习——文件输入输出与异常_编写程序处理输入输出异常,文件找不到异常。-优快云博客

本文介绍了Python中文件的基本操作，包括读取、写入及异常处理等，并演示了如何处理常见异常如ZeroDivisionError、FileNotFoundError等。此外，还展示了如何使用JSON模块来存储数据。

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1.读取文件

with open('learning_python.txt') as file_object:
	context = file_object.read()
	print(context)

with open('learning_python.txt') as file_object:	
	#遍历对象
	for line in file_object:
		print(line.rstrip())
	
print('\n')

with open('learning_python.txt') as file_object:	
	#逐行读取并将内容存储到列表,在with之外打印列表
	lines = file_object.readlines()
	
for each in lines:
	print(each.rstrip())

2.文件写入

# -*- coding: gbk -*-
file_name = 'create_write_file.txt'

with open(file_name,'w') as file_object:
	file_object.write('使用open时需指明参数，即以何种模式打开文件，默认为只读模式\n')
	file_object.write('写入文件时会刷新旧的内容，如果找不到目标文件会自动创建。\n')
	file_object.write('python只能将字符串写入文件，write方法不会添加换行符。\n')

3.异常处理

类型：ZeroDivisionError，FileNotFoundError，TypeError，ValueError

#ZeroDivisiomnError
a = 15
b = 0
try :
	print(a/b)
except ZeroDivisionError:
	mesg = 'can not divide by 0!\n'
	print(mesg)

#FileNotFoundError
file_name = 'abc.txt'

try:
	with open(file_name) as obj:
		txt = obj.read()
except FileNotFoundError:
	print('can not find the file ' + file_name +'!\n')
else:
	print(txt)
	
#ValueError
a = input("input a:\n")
b = input('input b:\n')
try:
	 c = int(a) + int(b)
except ValueError:
	print('please input numbers!!\n')
else:
	print(c)

4.存储数据

import json

file_name  = 'number.json'

try:
	with open(file_name) as obj:
		num = json.load(obj)
		
except FileNotFoundError:
	number = input('please input your favorious number:\n')
	with open(file_name,'w') as obj:
		json.dump(number,obj)
		print('I get your favorious number '+ number + ' now!')
else:
	print('your favorious number is '+num +'\n')

第一次输入;