文件操作

4.1 文件基本操作

f = open('a.txt',mode='r',encoding='utf-8')
f.read()
f.close()

4.2 打开模式

• r/w/a

• r+/w+/a+

• rb/wb/ab

• r+b/w+b/a+b

4.3 操作

• read(读取全部)

  • read(1) --> R模式下读取光标后一个字符

  --> rb模式下读取光标后一个字节

  #二进制模式下
  obj = open('a.txt',mode='rb')
  data = obj.read(3) # 1个字节
  obj.close()

   

• write()写入

  seek(移动光标位置,无论是否带b，都以字节为单位，移动相应的字节)

  obj = open('a.txt',mode='r',encoding='utf-8')
  obj.seek(3) # 跳转到指定字节位置
  data = obj.read()
  obj.close()
  ​
  print(data)
  ​
  ​
  ​
  ​
  obj = open('a.txt',mode='rb')
  obj.seek(3) # 跳转到指定字节位置
  data = obj.read()
  obj.close()
  ​
  print(data)

   

  flush()强制内存中的数据写入到硬盘

  v = open('a.txt',mode='a',encoding='utf-8')
  while True:
      val = input('请输入：')
      v.write(val)
      v.flush()
  ​
  v.close()

   

  tell() 获取光标当前所在字节位置

  obj = open('a.txt',mode='rb')
  # obj.seek(3) # 跳转到指定字节位置
  obj.read()
  data = obj.tell()
  print(data)
  obj.close()

   

4.4 关闭

一般方式：f.close()

特殊方式：with open("a.txt",mode='r',endcoding='utf-8') as v:

data = v.read() #缩进中的代码完成后自动关闭

4.5 文件内容的修改

with open("a.txt",mode="r",endcoding="utf-8")  as v:
     data = v.read()
    new_data = data.replace("贪玩"，"蓝月")
with open('b.txt',mode='w',endcoding='utf-8')  as v2:
    data = v2.write(new_data)

4.5.1大文件的修改

with open('a.txt',mode='r',encoding='utf-8') as f1, open('c.txt',mode='w',encoding='utf-8') as f2:
    for line in f1:
        new_line = line.replace('渣渣辉', '陈咬春')
        f2.write(new_line)