python io操作

一次性读取

 # 读取文件

 # 默认打开文件的方式是只读
 file = None
 try:
     file = open("f:/test.sql")
     print(file.name)  # f:/test.sql

     # read是一次性读取,调用read之后会把指针移动到文件的末尾,再次调用返回空字符串
     content = file.read()

     # print("----" + file.read())
     print(content)
 except Exception as log:
     print("找不到文件")
 finally:
     if file:
         file.close()

 # 使用with语句,with语句会自动帮我们调用close()
 with open("f:/test.sql") as f:
     print(f.read())

 # 使用with 可以创建单层级文件
 # with open("f:/ooooooooooooooooa.sql","w") as f:
 #     f.write("asd")

逐行读取

 # 逐行读取

 file = None
 try:
     file = open("f:/test.sql")

     line = file.readline()
     while line is not None and line.strip() != "":
         print(line)
         line = file.readline()

 except Exception as info:
     print("文件未找到")
 finally:
     if file is not  None:
         file.close()

逐行读取并写入

 # 逐行读取并写入
 rs = None
 ws = None
 try:
     rs = open("f:/test.sql")
     ws = open("f:/test_copy.sql", "w")

     # 读取并写入
     while True:
         line = rs.readline()

         # 如果line为None或者line为空字符串
         if line is None or line.strip() == "": # 或者 not line
             break
         ws.write(line)

 except Exception as info:
     print(info)
 finally:
     if rs:
         rs.close()
     if ws:
         ws.close()

字节流

 # -*- coding: utf-8 -*-
 # @author: Tele
 # @Time  : 2019/04/04 下午 12:17
 # 字节流读写
 rs = open("F:/ftp_mypc/a.flv", "rb")
 ws = open("f:/a_copy.flv", "wb")
 buffer = 1024
 while True:
     content = rs.read(buffer)
     if not content:
         break
     ws.write(content)

 if rs:
     rs.close()
 if ws:
     ws.close()