python_object_reference.py

a = set([hashabledict({1:11}), hashabledict({2:22})])
b = set([hashabledict({1:11}), hashabledict({3:33})])
for i in range(3):
    print "set a:", a
    delta = a-b
    print "delta", delta, id(delta)
    for item in delta:
        print id(item) #always same
        item[1] = "xx"
    print "*"*10

#--------------result-----------------
#set a: set([{1: 11}, {2: 22}]) 72004472
#delta set([{2: 22}]) 70757112
#70694736
#**********
#set a: set([{1: 11}, {1: 'xx', 2: 22}]) 72004472
#delta set([{1: 'xx', 2: 22}]) 72004712
#70694736
#**********
#set a: set([{1: 11}, {1: 'xx', 2: 22}]) 72004472
#delta set([{1: 'xx', 2: 22}]) 70757112
#70694736
#**********