:file:`JPEG` or :file:`EXE` files. Be very careful to use binary mode when

reading and writing such files.

It is good practice to use the :keyword:`with` keyword when dealing

with file objects. The advantage is that the file is properly closed

after its suite finishes, even if an exception is raised at some

point. Using :keyword:`with` is also much shorter than writing

equivalent :keyword:`try`\ -\ :keyword:`finally` blocks::

>>> with open('workfile') as f:

... read_data = f.read()

>>> f.closed

True

If you're not using the :keyword:`with` keyword, then you should call

``f.close()`` to close the file and immediately free up any system

resources used by it. If you don't explicitly close a file, Python's

garbage collector will eventually destroy the object and close the

open file for you, but the file may stay open for a while. Another

risk is that different Python implementations will do this clean-up at

different times.

After a file object is closed, either by a :keyword:`with` statement

or by calling ``f.close()``, attempts to use the file object will

automatically fail. ::

>>> f.close()

>>> f.read()

Traceback (most recent call last):

File "<stdin>", line 1, in <module>

ValueError: I/O operation on closed file

.. _tut-filemethods:

those returned from the ``f.tell()``, or zero. Any other *offset* value produces

undefined behaviour.

When you're done with a file, call ``f.close()`` to close it and free up any

system resources taken up by the open file. After calling ``f.close()``,

attempts to use the file object will automatically fail. ::

>>> f.close()

>>> f.read()

Traceback (most recent call last):

File "<stdin>", line 1, in <module>

ValueError: I/O operation on closed file

It is good practice to use the :keyword:`with` keyword when dealing with file

objects. This has the advantage that the file is properly closed after its

suite finishes, even if an exception is raised on the way. It is also much

shorter than writing equivalent :keyword:`try`\ -\ :keyword:`finally` blocks::

>>> with open('workfile', 'r') as f:

... read_data = f.read()

>>> f.closed

True

File objects have some additional methods, such as :meth:`~file.isatty` and

:meth:`~file.truncate` which are less frequently used; consult the Library

Reference for a complete guide to file objects.