New submission from Inada Naoki <[email protected]>:
-, |, and ^ of dictkeys are implemented as:
PyObject *result = PySet_New(self);
// Call set.difference_update, set.update, set.symmetric_difference_update with
other.
PySet_New(iterable) has optimized step for iterable is dict.
But since iterable is dictkeys, PyIter_Next() is called for all elements in the
dict.
We can pass dict instead of dictkey object to PySet_New.
$ ./python -m pyperf timeit -o patched.json -s 'k =
dict.fromkeys("abcdefghijklmnopqrstuvwxyz").keys(); s={1,2,3}' -- 'k | {1,2,3}'
$ ./python -m pyperf compare_to master.json patched.json
Mean +- std dev: [master] 778 ns +- 17 ns -> [patched] 550 ns +- 24 ns: 1.42x
faster (-29%)
----------
components: Interpreter Core
messages: 355536
nosy: inada.naoki
priority: normal
severity: normal
status: open
title: Optimize some set operations in dictkeys object
type: performance
versions: Python 3.9
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Python tracker <[email protected]>
<https://bugs.python.org/issue38613>
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