descriptor for objects doesn't apply to object, using __slots__

Question

Good morning,

I'm having a problem trying to use __ slots __ in one of my classes. I want to use it to optimize the creation of multiple instances of the Classifier object. I'm using Python 3.7.1.

This Works

class Classifier() :

    def __init__(self, own_storage, partner_storage, decision, strength) :

        self.own_storage = own_storage
        self.partner_storage = partner_storage
        self.decision = decision
        self.strength = strength

This doesn't work

class Classifier() :

    __slots__ = ('own_storage', 'partner_storage', 'decision', 'strength')

    def __init__(self, own_storage, partner_storage, decision, strength) :

        self.own_storage = own_storage
        self.partner_storage = partner_storage
        self.decision = decision
        self.strength = strength

Here is where I create all the instances of Classifier (It is a method of another class)

def allClassifiers(self) :

        cs = []
        own_range = []
        partner_range = []

        for i in range(1, self.agent.model.n_types + 1) :

            own_range.append(i)
            own_range.append(-i)
            partner_range.append(i)
            partner_range.append(-i)


        for own in own_range :

            for partner in partner_range :

                for decision in [0, 1] :

                    cs.append(Classifier(own, partner, decision, i))

        return cs  

The error I'm getting:

Traceback (most recent call last):

  File "C:\Users\Diru\Desktop\Internship\Sketch\classes\test.py", line 53, in <module>
    m = Model(10000, 1, 1, init_distribution = [0, 1, 1, 0], state_t = "uniform")

  File "C:\Users\Diru\Desktop\Internship\Sketch\classes\model.py", line 53, in __init__
    a = Agent(id_, i, self, production_i, h)

  File "C:\Users\Diru\Desktop\Internship\Sketch\classes\agent.py", line 31, in __init__
    self.cs = ClassifierSystem(self)

  File "C:\Users\Diru\Desktop\Internship\Sketch\classes\classifier_system.py", line 17, in __init__
    self.classifiers = self.allClassifiers()

  File "C:\Users\Diru\Desktop\Internship\Sketch\classes\classifier_system.py", line 41, in allClassifiers
    cs.append(Classifier(own, partner, decision, i))

  File "C:\Users\Diru\Desktop\Internship\Sketch\classes\classifier.py", line 7, in __init__
    self.own_storage = own_storage

TypeError: descriptor 'own_storage' for 'Classifier' objects doesn't apply to 'Classifier' object

I've seen multiple examples on how to use __ slots __ but I can't get where I'm making a mistake. Thank you for your help.

EDIT: If I try this code, it works

class Classifier() :

    __slots__ = ('own_storage', 'partner_storage', 'decision', 'strength')

    def __init__(self, own_storage, partner_storage, decision, strength) :

        self.own_storage = own_storage
        self.partner_storage = partner_storage
        self.decision = decision
        self.strength = strength

    c = []
    for i in range(0, 70) :      
        c.append(Classifier(1, 2, 1, i))

Also, if I put the last 3 lines of this code inside the allClassifiers function (third section of code I put in the question), it works.

EDIT 2: There is something I don't get with how Spyder works. Running the program from shell, it works perfectly in any case. With Spyder, after deleting the variables of the previous run, now the slot version works, and the version without it gives me this error:

Traceback (most recent call last):

  File "C:\Users\Diru\Desktop\Internship\Sketch\classes\test.py", line 53, in <module>
    m = Model(10000, 1, 1, init_distribution = [0, 1, 1, 0], state_t = "uniform")

  File "C:\Users\Diru\Desktop\Internship\Sketch\classes\model.py", line 53, in __init__
    a = Agent(id_, i, self, production_i, h)

  File "C:\Users\Diru\Desktop\Internship\Sketch\classes\agent.py", line 31, in __init__
    self.cs = ClassifierSystem(self)

  File "C:\Users\Diru\Desktop\Internship\Sketch\classes\classifier_system.py", line 17, in __init__
    self.classifiers = self.allClassifiers()

  File "C:\Users\Diru\Desktop\Internship\Sketch\classes\classifier_system.py", line 41, in allClassifiers
    cs.append(Classifier(own, partner, decision, i))

  File "C:\Users\Diru\Desktop\Internship\Sketch\classes\classifier.py", line 7, in __init__
    self.own_storage = own_storage

AttributeError: 'Classifier' object has no attribute 'own_storage'

At least now I know that the problem is that I don't know how to use Spyder

Answer 1

I was facing the same issue.
Solution: Restart Spyder.
Hope it solves the issue.