Python问题： NameError: name 'regr_1' is not defined

python2021 

导入相关模块和sys什么的都试过了，就是解决不了

#coding=utf-8
from sklearn import tree
from IPython.display import Image
from sklearn import tree
import pydotplus

#regr_1 和regr_2
dot_data = tree.export_graphviz(regr_1, out_file=None,  #regr_1 是对应分类器
                         feature_names=['x'],   #对应特征的名字
                         class_names=['y'],    #对应类别的名字
                         filled=True, rounded=True,
                         special_characters=True)
graph = pydotplus.graph_from_dot_data(dot_data)
graph.write_png('example.png')    #保存图像
Image(graph.create_png())

就是报错：

NameError: name 'regr_1' is not defined

请问有人知道是哪里出了问题吗

下面这行代码regr_1的变量是哪里来的？

dot_data = tree.export_graphviz(regr_1, out_file=None, #regr_1 是对应分类器

feature_names=['x'], #对应特征的名字

class_names=['y'], #对应类别的名字

filled=True, rounded=True,

special_characters=True)

都告诉你regr_1没定义了

https://blog.csdn.net/bryant_meng/article/details/79616408?ops_request_misc=%257B%2522request%255Fid%2522%253A%2522161847662016780269810066%2522%252C%2522scm%2522%253A%252220140713.130102334..%2522%257D&request_id=161847662016780269810066&biz_id=0&utm_medium=distribute.pc_search_result.none-task-blog-2~all~sobaiduend~default-2-79616408.first_rank_v2_pc_rank_v29&utm_term=python%E4%B8%ADsklearn%E5%AE%9E%E7%8E%B0%E5%86%B3%E7%AD%96%E6%A0%91%E5%8F%AF%E8%A7%86%E5%8C%96忘放原博链接了