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author | Georg Brandl <georg@python.org> | 2008-07-16 23:35:54 (GMT) |
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committer | Georg Brandl <georg@python.org> | 2008-07-16 23:35:54 (GMT) |
commit | a66bb0a741060b35151673dffb0d5b87307aa7e9 (patch) | |
tree | 787db3acd08046edfe382ebbb6c365b4f4afc45d /Doc/tutorial | |
parent | 0a34baf1fc10ffd61f4e9a8d053008dd57930fff (diff) | |
download | cpython-a66bb0a741060b35151673dffb0d5b87307aa7e9.zip cpython-a66bb0a741060b35151673dffb0d5b87307aa7e9.tar.gz cpython-a66bb0a741060b35151673dffb0d5b87307aa7e9.tar.bz2 |
#3388: add a paragraph about using "with" for file objects.
Diffstat (limited to 'Doc/tutorial')
-rw-r--r-- | Doc/tutorial/inputoutput.rst | 10 |
1 files changed, 10 insertions, 0 deletions
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 "<stdin>", 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. |