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| author | Raymond Hettinger <rhettinger@users.noreply.github.com> | 2019-04-28 07:22:36 (GMT) |
|---|---|---|
| committer | GitHub <noreply@github.com> | 2019-04-28 07:22:36 (GMT) |
| commit | da63b321f63b697f75e7ab2f88f55d907f56c187 (patch) | |
| tree | 598845d2bf6291eefde3b9361fc394c5edec7990 /Doc | |
| parent | 50fed0b64faa3053300008ef5607b570fe209de6 (diff) | |
| download | cpython-da63b321f63b697f75e7ab2f88f55d907f56c187.zip cpython-da63b321f63b697f75e7ab2f88f55d907f56c187.tar.gz cpython-da63b321f63b697f75e7ab2f88f55d907f56c187.tar.bz2 | |
bpo-36715: Add usage note for dict.fromkeys() (GH-12974)
Diffstat (limited to 'Doc')
| -rw-r--r-- | Doc/library/stdtypes.rst | 5 |
1 files changed, 4 insertions, 1 deletions
diff --git a/Doc/library/stdtypes.rst b/Doc/library/stdtypes.rst index aeecdbb..0a6bb14 100644 --- a/Doc/library/stdtypes.rst +++ b/Doc/library/stdtypes.rst @@ -4254,7 +4254,10 @@ pairs within braces, for example: ``{'jack': 4098, 'sjoerd': 4127}`` or ``{4098: Create a new dictionary with keys from *iterable* and values set to *value*. :meth:`fromkeys` is a class method that returns a new dictionary. *value* - defaults to ``None``. + defaults to ``None``. All of the values refer to just a single instance, + so it generally doesn't make sense for *value* to be a mutable object + such as an empty list. To get distinct values, use a :ref:`dict + comprehension <dict>` instead. .. method:: get(key[, default]) |