はじめに

タイトルのとおりです。

コード

import ast
import nbformat
from nbconvert import PythonExporter
from nbconvert.preprocessors import Preprocessor

class LastExprToPrintPreprocessor(Preprocessor):
    def preprocess_cell(self, cell, resources, index):
        if cell.cell_type == "code" and cell.source.strip():
            try:
                tree = ast.parse(cell.source)
                if tree.body and isinstance(tree.body[-1], ast.Expr):
                    # セル最後の行が変数なら print(...) に置換
                    last_expr = tree.body[-1].value
                    print_call = ast.Expr(
                        value=ast.Call(
                            func=ast.Name(id="print", ctx=ast.Load()),
                            args=[last_expr],
                            keywords=[]
                        )
                    )
                    tree.body[-1] = print_call
                    cell.source = ast.unparse(tree)
            except Exception:
                pass
        return cell, resources


def convert_with_last_expr_print(
    ipynb_path,
    py_path
):
    nb = nbformat.read(ipynb_path, as_version=4)
    exporter = PythonExporter()
    exporter.register_preprocessor(LastExprToPrintPreprocessor, enabled=True)
    body, _ = exporter.from_notebook_node(nb)
    with open(py_path, "w", encoding="utf-8") as f:
        f.write(body)

使い方

ipynb_path: ipynbファイルの場所
py_path: pyファイルを出力先

convert_with_last_expr_print(
    ipynb_path,
    py_path
)