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# Set operations in Numeric

Is there a way to handle numeric (or numarray or numpy) arrays as sets
and compute efficiently their intersection, union, etc. ? I hope there
is a faster way than s = array(set(A) & set(B)). Can this be done with
masked arrays maybe ? I've never used them though and browsing through
the docs didn't make clear if it is possible.

Thanks,
George

Oct 23 '06 #1
2 1080
George Sakkis wrote:
Is there a way to handle numeric (or numarray or numpy) arrays as sets
and compute efficiently their intersection, union, etc. ? I hope there
is a faster way than s = array(set(A) & set(B)). Can this be done with
masked arrays maybe ? I've never used them though and browsing through
the docs didn't make clear if it is possible.
You'll probably want to ask such questions on the numpy list:

http://www.scipy.org/Mailing_Lists

Robert Cimrman has implemented a number of set operations based on sorting.

http://svn.scipy.org/svn/scipy/trunk...arraysetops.py

--
Robert Kern

"I have come to believe that the whole world is an enigma, a harmless enigma
an underlying truth."
-- Umberto Eco

Oct 23 '06 #2
Robert Kern wrote:
George Sakkis wrote:
Is there a way to handle numeric (or numarray or numpy) arrays as sets
and compute efficiently their intersection, union, etc. ? I hope there
is a faster way than s = array(set(A) & set(B)). Can this be done with
masked arrays maybe ? I've never used them though and browsing through
the docs didn't make clear if it is possible.

You'll probably want to ask such questions on the numpy list:

http://www.scipy.org/Mailing_Lists

Robert Cimrman has implemented a number of set operations based on sorting.

http://svn.scipy.org/svn/scipy/trunk...arraysetops.py
Thank you so much, these fit the bill perfectly !

George

Oct 23 '06 #3

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