Why does python point two variables to a same memory address?

Question

I declared two variables in Python 3 and tried printing their memory addresses as:

num1 = 1
num2 = 1
print(hex(id(num1)))
print(hex(id(num2)))

turns out that both the addresses are the same. Why is it so unlike C and C++ where every variable has a unique memory address.

Your question has been closed as a dup because this particular example is a bit of a special case (in the reference CPython implementation at least). But there's more to it actually - Python's variables are totally different from C/C++ ones, they are not symbolic names for memory locations, but key=>value pairs where the key is the name and the value the object the name is bound to. This is very clearly explained in [this excellent article](https://nedbatchelder.com/text/names.html) that you definitly want to read. — bruno desthuilliers, Apr 17 '20 at 05:29

score 3 · Answer 1 · answered Apr 16 '20 at 14:29

3

Please read the answer here: https://stackoverflow.com/a/15172182/8733066

The python interpreter doesn't need tho save the value 1 multiple times because int is immutable. So all variables with the value four point to the same memory location.

answered Apr 16 '20 at 14:29

bb1950328

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score -4 · Answer 2 · answered Apr 16 '20 at 14:29

-4

Because that's how Python works. Everything is an object. Every number is an object. Every different string is an object. True and False are objects.

answered Apr 16 '20 at 14:29

Andy Lester

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This doesn't explain why two instances of an integer sometimes are the same object and sometimes not. – bruno desthuilliers Apr 16 '20 at 14:32
OP didn't ask that. – Andy Lester Apr 16 '20 at 19:10
please re-read the question - the op very clearly asks why two variables point to the same address. – bruno desthuilliers Apr 17 '20 at 05:22

Why does python point two variables to a same memory address?

2 Answers2