File methods

In this section i would like to show you some file methods.

Whenever we use open( ) function, a file object is created.

Ex

>>> f=open(“vms.txt”,’w+’)                                    #Created vms.txt file

The below are some of the functions to call on this object.

1.fileno( )

The method fileno( ) returns the integer file descriptor that is used by the underlying implementation to request I/O operations from the operating system.

 Syntax

fileObject.fileno( )

Ex

>>> f_id=f.fileno( ) >>> f_id 3

2.isatty( )

The method isatty( ) returns True if the file is connected (is associated with a terminal device) to a tty(-like) device, else False.

Syntax

fileObject.isatty( )

 Ex

>>> val=f.isatty( ) >>> val False

 3.write( )

The method write( ) writes a string str to the file.

Syntax

fileObject.write( str )

 Ex

>>> f=open(“vms.txt”,’w’) >>> f.write(“Some programming languages are:\nC\nC++\nJava\nPython\nPHP”) 53

 4.read( )

The method read( ) reads at most size bytes from the file. If the read hits EOF before obtaining size bytes, then it reads only available bytes.

Syntax

fileObject.read( size );

Ex

>>> f=open(“vms.txt”,’r’) >>> f.read(11) ‘Some progra’ >>> f.read(7) ‘mming l’ >>> f.read(1) ‘a’ >>> f.read( ) ‘Some programming languages are:\nC\nC++\nJava\nPython\nPHP’

 5.flush( )

The method flush( ) flushes the internal buffer, like stdio’s fflush. This may be a no-op on some file-like objects.Python automatically flushes the files when closing them.

Syntax

fileObject.flush( )

Ex

>>> f.flush( )

It prints nothing.

6.tell( )

It returns the current position of the file read/write pointer within the file.

Syntax

fileObject.tell( )

Ex

>>> f=open(“vms.txt”,’r’) >>> f.read(6) ‘Some p’ >>> f.tell( ) 6 >>> f.read(8) ‘rogrammi’ >>> f.tell( ) 14