对象没有属性错误（Google机器学习教程Ep.5）

Question

嗨，我的代码有点问题，我对python有点陌生，但我对类和对象有一些了解。你知道吗

import random
class ScrappyKNN():
    def fit(self,X_train,Y_train):
        self.X_train = X_train
        self.Y_train = Y_train
    def predict(self, X_test,a):
        predictions = []
        for row in X_test:
            label = random.choice(self.Y_train)
            predictions.append(label)
        return predictions

import numpy as np

from sklearn import datasets

iris = datasets.load_iris()

X = iris.data
Y = iris.target

from sklearn.model_selection import train_test_split
X_train,X_test,Y_train,Y_test = train_test_split(X,Y,test_size = .5)

#from sklearn.neighbours import KNeighboursClassifier
my_classifier = ScrappyKNN()

my_classifier = my_classifier.fit(X_train,Y_train)

predictions = my_classifier.predict(X_test)

from sklearn.metrics import accuracy_score
print(accuracy_score(Y_test, predictions))

但我运行它时出错了：

Traceback (most recent call last):
  File "pipelineKNeighbours.py", line 30, in <module>
    predictions = my_classifier.predict(X_test)
AttributeError: 'NoneType' object has no attribute 'predict'

我做错什么了？你知道吗

Answer 1

线路

my_classifier = my_classifier.fit(X_train,Y_train)

将我的\u分类器重新定义为fit（）的返回值，该值为None，因此我的\u分类器不再指向scrapyknn类的实例，而是指向一个NoneType对象-因此，出现了错误。你知道吗