读写文件的几种方式

手动方式

• open+close
• 三种模式
  w, write, 写
  r，read，读
  a， append，追加内容

import os     
 os.chdir(r'path') 切换到操作路径    
 f = open('de8ug.txt', 'w')     
 用w方式打开文件，不存在则创建     
 f.write('de8ug' * 8) # 写入字符串    
 f.close()

自动方式

• 相关模块

  • fnmatch
  • glob
  • pickle
  • StringIO
  • shelve

• with open

with open('de8ug-1.txt', 'w') as f:     
     f.write('de8ug')
with open('de8ug.txt') as f: 
    data = f.read()     
    print(data)
with open('de8ug.txt') as f:    
    print(f.readline()) *读取一行*
with open('de8ug.txt', 'a') as f:      
   'a' 多几行，追加到源文件    
    f.write('111111\n')     
    f.write('111111\n')      
    f.write('\n111111')      
    f.write('\n111111')      
with open('de8ug.txt') as f:   
    print(f.readlines())    #读取多行
#结果返回一个列表
['de8ugde8ugde8ugde8ugde8ugde8ugde8ugde8ug111111\n', '111111\n', '\n', '111111\n', '111111']

• fnmatch
  • 匹配相应后缀名的文件

import fnmatch    
for f in os.listdir('test'):    
    if fnmatch.fnmatch(f, '*.txt'):     
        print(f)     
    elif fnmatch.fnmatch(f, '\*.pdf'):     
        print('find pdf', f)

• *号匹配多个，若匹配单字符可用？号
• *正则，？匹配一个字符
  • glob
• 单纯匹配某种命名规则文件

import glob
for f in glob.glob('test/[0-9].doc'):
  print(f)
test\0.doc
test\1.doc
test\2.doc
test\3.doc
test\4.doc

• pickle
  • 序列化存储

# 序列化 pickle，持久化，存盘
# 后缀名随意，推荐pkl
# 存储Python的数据结构
name_list = ['de8ug', 'lilei', 'hmm']
data = {'name': name_list, 'age': (4,5,6)}
import pickle
with open('data.pkl', 'wb') as f: 
  # 使用‘wb’,通用二进制存储
  pickle.dump(data, f)
with open('data.pkl', 'rb') as f: 
  # 'rb', 读写都二进制
  data = pickle.load(f)
  print(data)
{'name': ['de8ug', 'lilei', 'hmm'], 'age': (4, 5, 6)}

• io
  • 虚拟化读写

# 虚拟文件，临时文件，不需要真的保存文件到磁盘
import io
output = io.StringIO()
output.write('第2行代码\n')
print('试一下print到文件：', file=output)
# 取出内容
contents = output.getvalue()
print(contents)
# 关闭文件，清理缓存
output.close()

• shelve
  • 用类似字典的方式存储任意的Python对象

import shelve
with shelve.open('de8ug.she') as so:
  so['de8ug'] = '存一下888888这个值'
with shelve.open('de8ug.she') as so:
  print(so['de8ug'])
存一下888888这个值