Jupyter notebook调用模块的解决办法

在学习到"8.6 将函数存储在模块中"部分时候，由于我用的是jupyter notebook，不能像教材上的操作进行，于是网络上找到了解决的办法，记录如下。

注释：python开发环境jupyter notebook良好的交互式和模块化受到很多python开发人员的青睐，但是jupyter notebook是以json格式保存文件内容的，而不是python文件那样的普通格式，所以不能直接被python解析器解析，如何调用.ipynb中的module也成为一个问题。本文介绍一种方法，使得只要在我们的工作目录下放置一个python文件，就可以正常调用其他jupyter notebook文件。

A. 教材上的操作：

1. 创建一个包含函数make_pizza()的模块，并命名为pizza.py，代码如下：

def make_pizza(size, *toppings):
    print("\nMaking a " + str(size) +
    "-inch pizza with the following topping:")
    for topping in toppings:
        print("- " + topping)

2. 然后在pizza.py所在的目录中创建另一个名为making_pizzas.py的文件，将这个文件导入刚创建的模块。

import pizza

pizza.make_pizza(16,"pepperoni")
pizza.make_pizza(12, "mushrooms","green peppers","extra cheese")

B. Jupyter解决办法：***

这种方法的本质就是使用一个jupyter notenook解析器先对.ipynb文件进行解析，把文件内的各个模块加载到内存里供其他python文件调用。

1. 添加jupyter notebook解析文件
   首先，创建一个python文件，例如Ipynb_importer.py，代码略长，附在文后。
2. 调用jupyter notebook module
   首先，在jupyter notebook文件里调用Ipynb_importer.py，然后，们就可以像调用普通python文件一样调用其他.ipynb文件里的module了。

import Ipynb_importer
import pizza

pizza.make_pizza(16,"pepperoni")
pizza.make_pizza(12, "mushrooms","green peppers","extra cheese")

Ipynb_importer.py 代码：

import io, os,sys,types
from IPython import get_ipython
from nbformat import read
from IPython.core.interactiveshell import InteractiveShell

class NotebookFinder(object):
    """Module finder that locates Jupyter Notebooks"""
    def __init__(self):
        self.loaders = {}

    def find_module(self, fullname, path=None):
        nb_path = find_notebook(fullname, path)
        if not nb_path:
            return

        key = path
        if path:
            # lists aren't hashable
            key = os.path.sep.join(path)

        if key not in self.loaders:
            self.loaders[key] = NotebookLoader(path)
        return self.loaders[key]

def find_notebook(fullname, path=None):
    """find a notebook, given its fully qualified name and an optional path

    This turns "foo.bar" into "foo/bar.ipynb"
    and tries turning "Foo_Bar" into "Foo Bar" if Foo_Bar
    does not exist.
    """
    name = fullname.rsplit('.', 1)[-1]
    if not path:
        path = ['']
    for d in path:
        nb_path = os.path.join(d, name + ".ipynb")
        if os.path.isfile(nb_path):
            return nb_path
        # let import Notebook_Name find "Notebook Name.ipynb"
        nb_path = nb_path.replace("_", " ")
        if os.path.isfile(nb_path):
            return nb_path

class NotebookLoader(object):
    """Module Loader for Jupyter Notebooks"""
    def __init__(self, path=None):
        self.shell = InteractiveShell.instance()
        self.path = path

    def load_module(self, fullname):
        """import a notebook as a module"""
        path = find_notebook(fullname, self.path)

        print ("importing Jupyter notebook from %s" % path)

        # load the notebook object
        with io.open(path, 'r', encoding='utf-8') as f:
            nb = read(f, 4)


        # create the module and add it to sys.modules
        # if name in sys.modules:
        #    return sys.modules[name]
        mod = types.ModuleType(fullname)
        mod.__file__ = path
        mod.__loader__ = self
        mod.__dict__['get_ipython'] = get_ipython
        sys.modules[fullname] = mod

        # extra work to ensure that magics that would affect the user_ns
        # actually affect the notebook module's ns
        save_user_ns = self.shell.user_ns
        self.shell.user_ns = mod.__dict__

        try:
          for cell in nb.cells:
            if cell.cell_type == 'code':
                # transform the input to executable Python
                code = self.shell.input_transformer_manager.transform_cell(cell.source)
                # run the code in themodule
                exec(code, mod.__dict__)
        finally:
            self.shell.user_ns = save_user_ns
        return mod
sys.meta_path.append(NotebookFinder())

参考资料：

1. 调用jupyter notebook文件内的函数一种简单方法
2. Importing Jupyter Notebooks as Modules