[Patches] [ python-Patches-597444 ] Speed-up sets

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Patches item #597444, was opened at 2002-08-19 17:57
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Category: Library (Lib)
Group: Python 2.3
Status: Open
Resolution: None
Priority: 5
Submitted By: Raymond Hettinger (rhettinger)
>Assigned to: Guido van Rossum (gvanrossum)
Summary: Speed-up sets

Initial Comment:
Gained a 5:1 speed-up for membership testing by 
handling the most common case first (the case 
where the element is hashable).

Also, renamed the popitem() method to pop() for 
consistency with list.pop and dict.pop(k).  The 'item' 
in popitem suggests that a tuple will be returned.

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Comment By: Raymond Hettinger (rhettinger)
Date: 2002-08-20 17:24

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Revised patch attached.

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Comment By: Raymond Hettinger (rhettinger)
Date: 2002-08-20 17:00

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Will do.

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Comment By: Guido van Rossum (gvanrossum)
Date: 2002-08-20 16:52

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I've implemented the popitem -> pop rename in CVS now.

Can you submit a reworked patch for the rest?

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Comment By: Guido van Rossum (gvanrossum)
Date: 2002-08-20 07:38

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Close. I agree with pop().

I agree that you can catch TypeError instead of being
prudent, but please use this idiom, which preserves the
traceback:

>>> try:
>>>   return element in self._data
>>> except TypeError:
>>>    transform = getattr(element,
"_as_temporary_immutable", None)
>>>    if transform is not None:
>>>       return transform() in self._data
>>>    else:
>>>       raise # re-raise the TypeError exception we caught

This *may* even be faster, because the AttributeError is
caught in C and never instantiated. But I don't care about
the speed of this so much as I care about preserving the
traceback -- and also about not hiding an AttributeError
that might happen inside the transform() call.

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Comment By: Raymond Hettinger (rhettinger)
Date: 2002-08-19 17:59

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Attached a script that verifies the claimed timing speed-up.

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