From a66bb0a741060b35151673dffb0d5b87307aa7e9 Mon Sep 17 00:00:00 2001 From: Georg Brandl Date: Wed, 16 Jul 2008 23:35:54 +0000 Subject: #3388: add a paragraph about using "with" for file objects. --- Doc/tutorial/inputoutput.rst | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/Doc/tutorial/inputoutput.rst b/Doc/tutorial/inputoutput.rst index fe33d12..1b344e6 100644 --- a/Doc/tutorial/inputoutput.rst +++ b/Doc/tutorial/inputoutput.rst @@ -348,6 +348,16 @@ attempts to use the file object will automatically fail. :: File "", line 1, in ? 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('/tmp/workfile', 'r') as f: + ... read_data = f.read() + >>> f.closed + True + File objects have some additional methods, such as :meth:`isatty` and :meth:`truncate` which are less frequently used; consult the Library Reference for a complete guide to file objects. -- cgit v0.12