Set operations on object attributes question

TheSeeker duane.kaufman at
Tue Oct 23 15:47:06 CEST 2007


I have run into something I would like to do, but am not sure how to
code it up. I would like to perform 'set-like' operations (union,
intersection, etc) on a set of objects, but have the set operations
based on an attribute of the object, rather than the whole object.

For instance, say I have (pseudo-code):

LoTuples1 = [(1,1,0),(1,2,1),(1,3,3)]
LoTuples2 = [(2,1,3),(2,2,4),(2,3,2)]

What I would like to be able to do is:

Set3 = Set1union(Set2)
Set3.intersection(Set2, <use object[2]>)

to return:
set([(2,1,3), (1,3,3)])

How can one do this operation?


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