How do I check if two variables reference the same object in Python?
PythonEqualityPython Problem Overview
x and y are two variables.
I can check if they're equal using x == y, but how can I check if they have the same identity?
Example:
x = [1, 2, 3]
y = [1, 2, 3]
Now x == y is True because x and y are equal, however, x and y aren't the same object.
I'm looking for something like sameObject(x, y) which in that case is supposed to be False.
Python Solutions
Solution 1 - Python
You can use is to check if two objects have the same identity.
>>> x = [1, 2, 3]
>>> y = [1, 2, 3]
>>> x == y
True
>>> x is y
False
Solution 2 - Python
Use x is y or id(x) == id(y).
They seem to be equivalent.
id(object) returns a unique number (identity) that adapts the philosophy of C-style pointer. For debugging id(x) == id(y) is more convient.
x is y is prettier.
== utilizes equal comparator object.__eq__(self, other)