https://github.com/python/cpython/commit/1d39dba759049ee330b5b35d8f0f46f2a283bc4c commit: 1d39dba759049ee330b5b35d8f0f46f2a283bc4c branch: 3.13 author: Miss Islington (bot) <[email protected]> committer: ZeroIntensity <[email protected]> date: 2025-10-06T13:11:49Z summary:
[3.13] gh-116488: Mention `dict.get` in the data structures tutorial (GH-139643) (GH-139656) gh-116488: Mention `dict.get` in the data structures tutorial (GH-139643) (cherry picked from commit 69cfad0b3e1e2805914cb647cce4c7c2bfed5910) Co-authored-by: Cycloctane <[email protected]> files: M Doc/tutorial/datastructures.rst diff --git a/Doc/tutorial/datastructures.rst b/Doc/tutorial/datastructures.rst index db8a066b369a83..1332c53f39687e 100644 --- a/Doc/tutorial/datastructures.rst +++ b/Doc/tutorial/datastructures.rst @@ -512,8 +512,12 @@ dictionary; this is also the way dictionaries are written on output. The main operations on a dictionary are storing a value with some key and extracting the value given the key. It is also possible to delete a key:value pair with ``del``. If you store using a key that is already in use, the old -value associated with that key is forgotten. It is an error to extract a value -using a non-existent key. +value associated with that key is forgotten. + +Extracting a value for a non-existent key by subscripting (``d[key]``) raises a +:exc:`KeyError`. To avoid getting this error when trying to access a possibly +non-existent key, use the :meth:`~dict.get` method instead, which returns +``None`` (or a specified default value) if the key is not in the dictionary. Performing ``list(d)`` on a dictionary returns a list of all the keys used in the dictionary, in insertion order (if you want it sorted, just use @@ -528,6 +532,12 @@ Here is a small example using a dictionary:: {'jack': 4098, 'sape': 4139, 'guido': 4127} >>> tel['jack'] 4098 + >>> tel['irv'] + Traceback (most recent call last): + File "<stdin>", line 1, in <module> + KeyError: 'irv' + >>> print(tel.get('irv')) + None >>> del tel['sape'] >>> tel['irv'] = 4127 >>> tel _______________________________________________ Python-checkins mailing list -- [email protected] To unsubscribe send an email to [email protected] https://mail.python.org/mailman3//lists/python-checkins.python.org Member address: [email protected]
