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author | Jörn Heissler <joernheissler@users.noreply.github.com> | 2019-06-22 14:40:55 (GMT) |
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committer | Miss Islington (bot) <31488909+miss-islington@users.noreply.github.com> | 2019-06-22 14:40:55 (GMT) |
commit | c8a35417db8853a253517a3e5190e174075c6384 (patch) | |
tree | 760e1a6590e7244315d4c8ac35acc8a0a6f6b736 /Doc/reference/expressions.rst | |
parent | bb110cc2ed81447fb48805f31146cf31323a8fc3 (diff) | |
download | cpython-c8a35417db8853a253517a3e5190e174075c6384.zip cpython-c8a35417db8853a253517a3e5190e174075c6384.tar.gz cpython-c8a35417db8853a253517a3e5190e174075c6384.tar.bz2 |
bpo-35224: Reverse evaluation order of key: value in dict comprehensions (GH-14139)
… as proposed in PEP 572; key is now evaluated before value.
https://bugs.python.org/issue35224
Diffstat (limited to 'Doc/reference/expressions.rst')
-rw-r--r-- | Doc/reference/expressions.rst | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/Doc/reference/expressions.rst b/Doc/reference/expressions.rst index 8b71106..432327a 100644 --- a/Doc/reference/expressions.rst +++ b/Doc/reference/expressions.rst @@ -337,6 +337,12 @@ all mutable objects.) Clashes between duplicate keys are not detected; the last datum (textually rightmost in the display) stored for a given key value prevails. +.. versionchanged:: 3.8 + Prior to Python 3.8, in dict comprehensions, the evaluation order of key + and value was not well-defined. In CPython, the value was evaluated before + the key. Starting with 3.8, the key is evaluated before the value, as + proposed by :pep:`572`. + .. _genexpr: |