id(object)
The id function returns the "identity" of an object, that is, a constant numeric value that uniquely identifies the object for as long as it is defined.
In Python, anything is an object, so we can get the identity from -even- the id function.
The identity of an object can vary from one execution of the code to another. Some objects always receive the same identity (integers between -5 and 256 inclusive, for example).
- object: object whose identity you want to obtain.
The id function returns an integer.
We can obtain the identity of the number 18 with the following code:
id(18)
140710254160192
This value will remain the same even after restarting the kernel.
We can obtain the identity of the id function with the following code:
id(id)
2520727620160
If two variables refer to the same object, their identity will be the same:
a = [1, 2]
b = a
dir(a) == dir(b)
True
Working with NumPy arrays, a view of an array receives a different identity than the one received by the array:
import numpy as np
a = np.array([1, 2, 3])
a
array ([1, 2, 3])
b = a[: 1]
b
array([1])
id(a) == id(b)
False
