Python文件的创建与写入

目录

• 利用内置函数open获取文件对象
• 文件操作的模式之写入
• 文件对象的操作方法之写入保存

利用内置函数open获取文件对象

• 功能:
  • 生成文件对象，进行创建，读写操作
• 用法:
  • open(path,mode)
• 参数说明∶
  • path:文件路径
  • mode :操作模式
• 返回值:
  • 文件对象
• 举例:
  • f = open('d://a.txt' , ‘w')

文件操作的模式之写入

文件对象的操作方法

In [1]: import os

In [2]: current_path = os.getcwd()

In [3]: current_path
Out[3]: 'D:\\My_Files\\Python Project\\pythonlean\\python_package'

In [4]: f = open(current_path + '/' + 'a.txt', 'w', encoding='utf-8')

In [5]: f.write('hello 小明')
Out[5]: 8

In [6]: f.close()

In [7]: path = os.path.join(current_path, 'a.txt')

In [8]: path
Out[8]: 'D:\\My_Files\\Python Project\\pythonlean\\python_package\\a.txt'

In [9]: f = open(path, 'w', encoding='utf=8')

In [10]: f.write('你好 小华')
Out[10]: 5

In [11]: f.close()

In [12]: f = open(path, 'w+', encoding='utf=8')

In [14]: f.write('你好 insane')
Out[14]: 9

In [15]: f.close()

In [16]: f = open(path, 'w', encoding='utf=8')

In [17]: f.write('hahaha')
Out[17]: 6

In [18]: f.read()
---------------------------------------------------------------------------
UnsupportedOperation                      Traceback (most recent call last)
<ipython-input-18-571e9fb02258> in <module>
----> 1 f.read()

UnsupportedOperation: not readable

In [19]: f.close()

In [20]: f = open(path, 'w+', encoding='utf=8')

In [21]: f.write("nono")
Out[21]: 4

In [22]: f.read()  # 默认为读取最后一个字符
Out[22]: ''

In [23]: f.seek(0)  # 指定从头开始读取
Out[23]: 0

In [24]: f.read()
Out[24]: 'nono'


In [28]: f = open(path, 'ab', encoding='utf-8')
---------------------------------------------------------------------------
ValueError                                Traceback (most recent call last)
<ipython-input-28-53d8520ae678> in <module>
----> 1 f = open(path, 'ab', encoding='utf-8')

ValueError: binary mode doesn't take an encoding argument


Unhandled exception in event loop:
  File "D:\Program Files\Python38\lib\asyncio\proactor_events.py", line 768, in _loop_self_reading
    f.result()  # may raise
  File "D:\Program Files\Python38\lib\asyncio\windows_events.py", line 808, in _poll
    value = callback(transferred, key, ov)
  File "D:\Program Files\Python38\lib\asyncio\windows_events.py", line 457, in finish_recv
    raise ConnectionResetError(*exc.args)

Exception [WinError 995] 由于线程退出或应用程序请求，已中止 I/O 操作。
Press ENTER to continue...
In [29]: f = open(path, 'ab', encoding='utf-8')
---------------------------------------------------------------------------
ValueError                                Traceback (most recent call last)
<ipython-input-29-53d8520ae678> in <module>
----> 1 f = open(path, 'ab', encoding='utf-8')

ValueError: binary mode doesn't take an encoding argument

In [30]: f = open(path, 'ab')

In [31]: f.write('Python很有意思')
---------------------------------------------------------------------------
TypeError                                 Traceback (most recent call last)
<ipython-input-31-06909b58890f> in <module>
----> 1 f.write('Python很有意思')

TypeError: a bytes-like object is required, not 'str'

In [32]: f.write(b'Python很有意思')
  File "<ipython-input-32-b260791cc53c>", line 1
    f.write(b'Python很有意思')
            ^
SyntaxError: bytes can only contain ASCII literal characters.


In [33]: message = 'python很有意思'

InIn [34]: 

In [34]: _message = message.encode('utf-8')

In [35]: _message
Out[35]: b'python\xe5\xbe\x88\xe6\x9c\x89\xe6\x84\x8f\xe6\x80\x9d'

In [36]: f.write(_message)
Out[36]: 18

In [37]: f.close()

In [38]: f = open(path, 'a+')

In [39]: f.write('1\n')
Out[39]: 2

In [40]: f.write('2\n')
Out[40]: 2

In [42]: f.close()

In [44]: l = ['今天天气很好', '很适合学习python', 'python是非常简单的语言']

In [45]: f = open(path, 'a')

In [46]: f.writelines(l)

In [47]: f.close()

In [48]: f = open(path, 'a', encoding='utf-8')

In [49]: l = ['今天天气很好\n', '很适合学习python\n', 'python是非常简单的语言\n']

In [50]: f.writelines(l)

In [51]: f.close()

实战

#!/usr/bin/python3
# -*- coding: utf-8 -*-
# @Time     : 2021/8/22 11:11
# @Author   : InsaneLoafer
# @File     : package_open.py

import os

def create_package(path):
    if os.path.exists(path):
        raise Exception('%s 已经存在不可创建' % path)
    os.makedirs(path)
    init_path = os.path.join(path, '__init__.py')
    f = open(init_path, 'w', encoding='utf-8')
    f.write('# coding:utf-8\n')
    f.close()

class Open(object):
    def __init__(self, path, mode='w', is_return=True):
        self.path = path
        self.mode = mode
        self.is_return = is_return

    def write(self, message):
        f = open(self.path, mode=self.mode, encoding='utf-8')
        try:
            if self.is_return and message.endswith('\n'):
                message = '%s\n' % message
            f.write(message)
        except Exception as e:
            print(e)
        finally:
            f.close()

if __name__ == '__main__':
    current_path = os.getcwd()
    # path = os.path.join(current_path, 'test2')
    # create_package(path)
    open_path = os.path.join(current_path, 'b.txt')
    o = Open(open_path)
    o.write('你好 娃娃')