运行python脚本时出现错误

Question

我正在做一本有关决策树的练习。

我复制粘贴了整个代码，并给了我NameError：未定义名称'dtc'

import pandas as pd 
import numpy as np 
import matplotlib.pyplot as plt

from sklearn.model_selection import train_test_split
from sklearn.tree import DecisionTreeClassifier

df = pd.read_csv('https://raw.githubusercontent.com/uiuc-cse/data-fa14/gh-pages/data/iris.csv')

#print(df.describe())
#print(df.dtypes)

df['petal_width'].plot.hist()
#plt.show()

all_inputs = df[['sepal_length', 'sepal_width', 'petal_length', 'petal_width']].values
all_classes = df['species'].values

(train_inputs, test_inputs, train_classes, test_classes) = train_test_split(all_inputs, all_classes, train_size=0.7, random_state=1)

classifier = DecisionTreeClassifier()
classifier.fit(train_inputs, train_classes)

print("Accuracy: ", dtc.score(test_inputs, test_classes))

有人可以帮助我理解为什么会发生此错误吗？

Answer 1

Alex，您需要正确检查变量。您已将classifier声明为DecisionTreeClassifier的变量，但最后使用的是dtc。将dtc替换为classifier：

print("Accuracy: ", classifier.score(test_inputs, test_classes))