• len(): Returns the number of elements in an object (e.g., a list, string, or dictionary).
• size (e.g., array.size in NumPy or sys.getsizeof()): Returns the memory size of an object.

Example:

import numpy as np

my_list = [1, 2, 3]
my_array = np.array(my_list)

print(len(my_list))  # Output: 3
print(my_array.size)  # Output: 3