https://github.com/python/cpython/commit/21ac0a7f4cf6d11da728b33ed5e8cfa65a5a8ae7 commit: 21ac0a7f4cf6d11da728b33ed5e8cfa65a5a8ae7 branch: main author: Victorien <[email protected]> committer: AlexWaygood <[email protected]> date: 2024-10-11T23:05:13Z summary:
gh-116938: Clarify documentation of `dict` and `dict.update` regarding the positional argument they accept (#125213) Co-authored-by: Alex Waygood <[email protected]> files: M Doc/library/stdtypes.rst M Lib/_collections_abc.py diff --git a/Doc/library/stdtypes.rst b/Doc/library/stdtypes.rst index 833c71c4ce4b9a..a6e2e3b8928ebe 100644 --- a/Doc/library/stdtypes.rst +++ b/Doc/library/stdtypes.rst @@ -4505,14 +4505,14 @@ can be used interchangeably to index the same dictionary entry. ``dict([('foo', 100), ('bar', 200)])``, ``dict(foo=100, bar=200)`` If no positional argument is given, an empty dictionary is created. - If a positional argument is given and it is a mapping object, a dictionary - is created with the same key-value pairs as the mapping object. Otherwise, - the positional argument must be an :term:`iterable` object. Each item in - the iterable must itself be an iterable with exactly two objects. The - first object of each item becomes a key in the new dictionary, and the - second object the corresponding value. If a key occurs more than once, the - last value for that key becomes the corresponding value in the new - dictionary. + If a positional argument is given and it defines a ``keys()`` method, a + dictionary is created by calling :meth:`~object.__getitem__` on the argument with + each returned key from the method. Otherwise, the positional argument must be an + :term:`iterable` object. Each item in the iterable must itself be an iterable + with exactly two elements. The first element of each item becomes a key in the + new dictionary, and the second element the corresponding value. If a key occurs + more than once, the last value for that key becomes the corresponding value in + the new dictionary. If keyword arguments are given, the keyword arguments and their values are added to the dictionary created from the positional argument. If a key @@ -4669,10 +4669,11 @@ can be used interchangeably to index the same dictionary entry. Update the dictionary with the key/value pairs from *other*, overwriting existing keys. Return ``None``. - :meth:`update` accepts either another dictionary object or an iterable of - key/value pairs (as tuples or other iterables of length two). If keyword - arguments are specified, the dictionary is then updated with those - key/value pairs: ``d.update(red=1, blue=2)``. + :meth:`update` accepts either another object with a ``keys()`` method (in + which case :meth:`~object.__getitem__` is called with every key returned from + the method). or an iterable of key/value pairs (as tuples or other iterables + of length two). If keyword arguments are specified, the dictionary is then + updated with those key/value pairs: ``d.update(red=1, blue=2)``. .. method:: values() diff --git a/Lib/_collections_abc.py b/Lib/_collections_abc.py index c2edf6c8856c21..06667b7434ccef 100644 --- a/Lib/_collections_abc.py +++ b/Lib/_collections_abc.py @@ -962,7 +962,7 @@ def clear(self): def update(self, other=(), /, **kwds): ''' D.update([E, ]**F) -> None. Update D from mapping/iterable E and F. - If E present and has a .keys() method, does: for k in E: D[k] = E[k] + If E present and has a .keys() method, does: for k in E.keys(): D[k] = E[k] If E present and lacks .keys() method, does: for (k, v) in E: D[k] = v In either case, this is followed by: for k, v in F.items(): D[k] = v ''' _______________________________________________ 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]
