scope - Python set won't perform union -

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i have class member defined:

self.myset = set()

when perform myobject.myset.add('item'), using instance of class, works fine: print(myobject.myset) gives me {'item'} .

however, when perform myobject.myset.union(yourset), yourset not empty, won't work; print(myobject.myset) still prints empty set. why 1 method (add) working while (union) quietly (no exception thrown) failing? myobject.myset = yourset works, union in particular won't.

i'm using python 3.

set.union() not modify old set in-place, set.add() does. set.union() returns new set instead.

myobject.myset = myobject.myset.union(yourset)

this should trick. see python documentation on set.union() more information.


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