ipython - %load_ext 如何在 ipython 中工作

Question

我安装包:https://github.com/jaysw/ipydb

根据教程，我应该使用它来启用它，

$ ipython
In [1] : %load_ext ipydb

它看起来像一个 IPython 扩展。

但我感到困惑，这个包没有安装在我的“~/.ipython/extensions ”下

aaron@aarons-MacBook-Pro:~/Desktop/github/ipydb$ls ~/.ipython/extensions/
aaron@aarons-MacBook-Pro:~/Desktop/github/ipydb$ls ~/.ipython/nbextensions/
livereveal usability

所以，我想知道

%load_ext 魔法是如何工作的，或者当我输入“%load_ext ipydb”时发生了什么

如果我只输入“ipython ”，ipython 如何进行配置，它将使用默认配置文件，但我的“~/.ipython/profile_default/”下没有配置文件

下面是默认配置文件和一个用户定义的配置文件:

aaron@aarons-MacBook-Pro:~/Desktop/github/ipydb$ls ~/.ipython/profile_default/
db             history.sqlite log            nbconfig       pid            security       startup        static
aaron@aarons-MacBook-Pro:~/Desktop/github/ipydb$ipython profile create my_profile
[ProfileCreate] Generating default config file: u'/Users/aaron/.ipython/profile_my_profile/ipython_config.py'
[ProfileCreate] Generating default config file: u'/Users/aaron/.ipython/profile_my_profile/ipython_kernel_config.py'
[ProfileCreate] Generating default config file: u'/Users/aaron/.ipython/profile_my_profile/ipython_console_config.py'
[ProfileCreate] Generating default config file: u'/Users/aaron/.ipython/profile_my_profile/ipython_qtconsole_config.py'
[ProfileCreate] Generating default config file: u'/Users/aaron/.ipython/profile_my_profile/ipython_notebook_config.py'
[ProfileCreate] Generating default config file: u'/Users/aaron/.ipython/profile_my_profile/ipython_nbconvert_config.py'
aaron@aarons-MacBook-Pro:~/Desktop/github/ipydb$ls ~/.ipython/profile_my_profile/
ipython_config.py           ipython_nbconvert_config.py log                         startup
ipython_console_config.py   ipython_notebook_config.py  pid                         static
ipython_kernel_config.py    ipython_qtconsole_config.py security
aaron@aarons-MacBook-Pro:~/Desktop/github/ipydb$

谢谢，

Answer 1

好的，最后，我刚刚找到了在 ipython 中加载扩展的逻辑:

源代码在:https://github.com/ipython/ipython/blob/master/IPython/core/extensions.py

核心逻辑是:

def load_extension(self, module_str):
        """Load an IPython extension by its module name.
        Returns the string "already loaded" if the extension is already loaded,
        "no load function" if the module doesn't have a load_ipython_extension
        function, or None if it succeeded.
        """
        if module_str in self.loaded:
            return "already loaded"

        from IPython.utils.syspathcontext import prepended_to_syspath

        with self.shell.builtin_trap:
            if module_str not in sys.modules:
                with prepended_to_syspath(self.ipython_extension_dir):
                    __import__(module_str)
            mod = sys.modules[module_str]
            if self._call_load_ipython_extension(mod):
                self.loaded.add(module_str)
            else:
                return "no load function"

现在说得通了，感谢 IPython 团队构建了如此出色的工具，我真的很喜欢它。