PERF: add shortcut to Timedelta constructor #31070
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Same as in the Timestamp shortcut, we could hoist the shortcut to the very top of |
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What kind of performance gain does this show? |
WillAyd
added
Performance
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@WillAyd About 20% on 10 000 000 iterations. |
| # Test for #30543 | ||
| expected = pd.Timedelta(np.timedelta64(1, "s")) | ||
| result = pd.Timedelta(expected) | ||
| assert result is expected |
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I'm not sure about this expectation - we don't do this for Timestamps so not sure should do it for Timedeltas as well but maybe @jschendel has thoughts
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There is a test for the constructor identity too, in the Timestamp shortcut PR #30676. Sorry for posting the Timedelta one before that one gets merged. It's just that the discussion was mostly done there, so I thought I'd get on the Timedelta one too.
If it's inconvenient, then we can put this one on hold until #30676 gets merged, and then I can just copy the approach we settle on there.
| def setup(self): | ||
| self.nptimedelta64 = np.timedelta64(3600) | ||
| self.dttimedelta = datetime.timedelta(seconds=3600) | ||
| self.td = Timedelta(3600, unit="s") |
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Since we are here, let's add a benchmark for making Timedelta out of Timedelta, and I think we should also tweak existing tests. Currently, we benchmark both our method and np.timedelta64 and datetime.timedelta at the same time. We should move the initialization into setup, in my opinion. It's a bit nitpicky, of course, since both np.timedelta64 and datetime.timedelta are unlikely to change speed in the future, but still.
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thanks @AlexKirko |
WIP until #30676 gets merged.
black pandasgit diff upstream/master -u -- "*.py" | flake8 --diffThis implements a shortcut in the Timedelta constructor to cut down on processing if Timedelta is passed. We still need to check if any other args are passed. Then, if a Timedelta with no other kwargs was passed, we just return that same Timedelta.
A test is added to check that the Timedelta is still the same object.