3、文件常用的操作方法

3、文件常用的操作方法

                 read  write seek readline  read(n) readlines

                

                 readable() writeable()  判断是否可读或者可写

                         f1 = open('七个男人与一个女人', encoding='utf-8', mode='r')

                         print(f1.readable())   #True

                         print(f1.writable())   #False

                         f1.close()

                        

                 seek：按照字节去调整光标

                         f1 = open('七个男人与一个女人', encoding='utf-8')

                         f1.seek(3)

                         print(f1.read())

                         f1.close()

                        

                 seek(0,2)把光标调整到最后

                        

                 tell：告诉光标的位置

                         f1 = open('七个男人与一个女人', encoding='utf-8', mode='r')

                         f1.seek(3)

                         print(f1.tell())

                         f1.read()

                         print(f1.tell())

                         f1.close()

                

                 truncate： 对原文件的内容进行截取，以字节形式，只能在a模式下使用

                         f1 = open('七个男人与一个女人', encoding='utf-8', mode='a')

                         f1.truncate(3)

                         f1.close()

        文件的另一种操作方法：

                 with open() as 不用主动关闭 f1.close()

                 同一个open可以操作多个文件

                 with open()

                

                         with open('log1', encoding='utf-8') as f1:

                                  print(f1.read())

                         with open('log1', encoding='utf-8') as f1,\

                                  open('log2',encoding='utf-8', mode='w') as f2:

                                  print(f1.read())

                                  f2.write('666')

       

                         with open('log1', encoding='utf-8') as f1:

                         content = f1.read()

                         f1.close()

                         pass

                         with open('log1', encoding='utf-8',mode='w') as f2:

                                  f2.write('1234')