基于CHAID的FileNotFoundError决策树绘制

Question

我使用以下代码来获取CHAID的决策树

independent_variable_columns = ['gender', 'grade', 'no_renewals', 'complaint_count']
dep_variable = 'switch'
tree = Tree.from_pandas_df(
    df,
    dict(zip(independent_variable_columns, ['nominal'] * 38)),
    dep_variable,
    max_depth=2
)
tree.to_tree()
tree.render()

但是我得到了以下错误

  File "C:\Users\data\AppData\Local\Continuum\anaconda3\lib\site-packages\CHAID\graph.py", line 93, in <listcomp>
    [os.remove(file) for file in self.files]
FileNotFoundError: [WinError 3] The system cannot find the path specified: '/tmp/157840175993116164207458496094.png'

Answer 1

当涉及到生成文件名和处理临时文件时，该特定库没有实现最佳实践。这使得他们的代码在Windows上以各种方式崩溃。

我在similar issue with the same root cause上发表了评论，提出了解决这些问题的建议。

您可以通过运行以下代码在本地修复此问题：

import os
from datetime import datetime
from tempfile import TemporaryDirectory

import plotly.io as pio
import colorlover as cl
from graphviz import Digraph

from CHAID import graph

def Graph_render(self, path, view):
    if path is None:
        path = os.path.join("trees", f"{datetime.now():%Y-%m-%d %H:%M:%S}.gv")
    with TemporaryDirectory() as self.tempdir:
        g = Digraph(
            format="png",
            graph_attr={"splines": "ortho"},
            node_attr={"shape": "plaintext", "labelloc": "b"},
        )
        for node in self.tree:
            image = self.bar_chart(node)
            g.node(str(node.node_id), image=image)
            if node.parent is not None:
                edge_label = f"     ({', '.join(map(str, node.choices))})     \n ")
                g.edge(str(node.parent), str(node.node_id), xlabel=edge_label)

        g.render(path, view=view)

def Graph_bar_chart(self, node):
    fig = {
        "data": [
            {
                "values": list(node.members.values()),
                "labels": list(node.members),
                "showlegend": node.node_id == 0,
                "domain": {"x": [0, 1], "y": [0.4, 1.0]},
                "hole": 0.4,
                "type": "pie",
                "marker_colors": cl.scales["5"]["qual"]["Set1"],
            },
        ],
        "layout": {
            "margin_t": 50,
            "annotations": [{"font_size": 18, "x": 0.5, "y": 0.5}, {"y": [0, 0.2]}],
        },
    }

    if not node.is_terminal:
        p = None if node.p is None else format(node.p, ".5f")
        score = None if node.score is None else format(node.score, ".2f")
        self.append_table(fig, [p, score, node.split.column])

    filename = os.path.join(self.tempdir, f"node-{node.node_id}.png")
    pio.write_image(fig, file=filename, format="png")
    return filename

graph.Graph.render = Graph_render
graph.Graph.bar_chart = Graph_bar_chart

上面是对该库中Graph类的两个方法的重构，切换到使用tempdir.TemporaryDirectory()处理临时文件，并清理了文件名的生成方式。我还擅自清理了代码中的一些小问题。

我已经把它变成了一个pull request to update the project itself。