将另一个类导入一个类python

Question

I would like to be able to import class A into class B and use the functions present in class B. Something like the following:

from scipy import stats
import numpy as np

class TestLearner(object):

    def __init__(self, param1 = 2):
        self.param = param1

    def train_model(self, X, y):
        slope, intercept, r_value, p_value, std_err = stats.linregress(X,y)
        self.slope = slope
        self.intercept = intercept

    def predict_new(self, X):
        y = self.intercept + self.slope * X
        return y

class Test(object):

    def __init__(self, learner):
        self.learner = learner

    def add_evidence(self, X, y):
        learner = self.learner
        slope, intercept = learner.train_model(X,y)
        self.slope = slope
        self.intercept = intercept

    def predict(self, X):
        y= self.intercept * self.slope * X
        return y

import TestLearner as t

x_train = np.random.randn(10,3)
y_train = np.random.randn(10,)

x_test = np.random.randn(5,3)

testing = Test(learner = t.TestLearner)
testing.add_evidence(X=x_train,y= y_train)

I get the following error:

Traceback (most recent call last):
  File "<input>", line 40, in <module>
  File "<input>", line 26, in add_evidence
TypeError: train_model() missing 1 required positional argument: 'y'

Which I don't understand. It seems that the train model is looking for "self" as an input and I thought that was self contained in the TestLearner class?

Answer 1

In order to call a method within a class , you need to initilize that class into an instance ,you can initialize your instance in the Test constructor , but this only works if you pass into Test() another class and not an instance

class Test(object):

    def __init__(self, learner):
        self.learner = learner()

    def add_evidence(self, X, y):
        learner = self.learner
        slope, intercept = learner.train_model(X,y)
        self.slope = slope
        self.intercept = intercept

    def predict(self, X):
        y= self.intercept * self.slope * X
        return y