Overwriting a class attribute after returning it in method-CodePudding

I have a class method which constructs a numpy array as a class attribute. I want this attribute to be set to None after it is returned. I'm using an attribute instead of a variable because the creating the array is done in a parallel way. These arrays can be very large so I want to avoid having it in memory twice. What would be the best way to do this?

import numpy as np

class foo:
    
    def __init__(self):
        self.values = None
    
    def bar(self):
        self.values = np.arange(1e9)  # Large array
        return self.values
        self.values = None  # To be set to None after returning

CodePudding user response：

Python does not copy objects on assignment, it only passes a reference to the same object.

return np.arange(1e9) will simply return a reference to the created array. Creating any new variable holding it, like var = np.arange(1e9), will just assign a reference of the array to the variable.

You're welcome to visualize it if it helps.