Reference
ast
nomail at invalid.com
Mon Mar 3 04:42:30 EST 2014
hello
Consider following code:
>>> A=7
>>> B=7
>>> A is B
True
I understand that there is a single object 7 somewhere in memory and
both variables A and B point toward this object 7
now do the same with a list:
>>> l1 = [1, 2]
>>> l2 = [1, 2]
>>> l1 is l2
False
It seems this time that there are 2 distincts objects [1, 2] in memory. l1 points
toward the first one and l2 points toward the second one.
if I change one, the second remains unchanged
>>> l1.append(3)
>>> l1
[1, 2, 3]
>>> l2
[1, 2]
I dont really understand why the behavior is different.
Both integer 7 and list [1, 2] are objects. Why is it
different ?
thanks
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