python 文件交互基础

• File
• • `1. 工作目录`
  • • 1.1 `查看当前目录`
    • 1.1 `查看目录是否存在`
  • `2. 读文件`
  • `2. 读文件`
  • `3. 写文件`

import os

current_file = os.path.realpath('file_io.ipynb')  
print('current file: {}'.format(current_file))
# .py 脚本可使用 __file__

current_dir = os.path.dirname(current_file)  
print('current directory: {}'.format(current_dir))
#.py脚本可以使用os.path.dirname(__file__)

data_dir = os.path.join(os.path.dirname(current_dir), 'data')
print('data directory: {}'.format(data_dir))

print('exists: {}'.format(os.path.exists(data_dir)))
print('is file: {}'.format(os.path.isfile(data_dir)))
print('is directory: {}'.format(os.path.isdir(data_dir)))

file_path = os.path.join(data_dir, 'simple_file.txt')

with open(file_path, 'r') as simple_file:
    for line in simple_file:
        print(line.strip())

• with open 结束时不用调用close

file_path = os.path.join(data_dir, 'simple_file.txt')

with open(file_path, 'r') as simple_file:
    for line in simple_file:
        print(line.strip())

• open 结束时必须调用close

file_path = os.path.join(data_dir, 'simple_file.txt')


simple_file = open(file_path, 'r')
for line in simple_file:
    print(line.strip())
simple_file.close()

new_file_path = os.path.join(data_dir, 'new_file.txt')

with open(new_file_path, 'w') as my_file:
    my_file.write('This is my first file that I wrote with Python.')