Section 9.1. File Objects

9.1. File Objects

File objects can be used to access not only normal disk files, but also any other type of "file" that uses that abstraction. Once the proper "hooks" are installed, you can access other objects with file-style interfaces in the same manner you would access normal files.

You will find many cases where you are dealing with "file-like" objects as you continue to develop your Python experience. Some examples include "opening a URL" for reading a Web page in real-time and launching a command in a separate process and communicating to and from it like a pair of simultaneously open files, one for write and the other for read.

The open() built-in function (see below) returns a file object that is then used for all succeeding operations on the file in question. There are a large number of other functions that return a file or file-like object. One primary reason for this abstraction is that many input/output data structures prefer to adhere to a common interface. It provides consistency in behavior as well as implementation. Operating systems like Unix even feature files as an underlying and architectural interface for communication. Remember, files are simply a contiguous sequence of bytes. Anywhere data need to be sent usually involves a byte stream of some sort, whether the stream occurs as individual bytes or blocks of data.