Ipython Ninjitsu
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??sourcecode * %debug * %history * %reset * !shell commands

Date: December 14, 2020

- ?docstring
- ??sourcecode
- %run
- %debug
- %autoreload
- %history
- autoformat
- %reset
- !shell commands

?docstring
──────────

Stop going to google everytime your stuck and stay in your workflow. The ipython ? is a superhero for productivity and staying on task.

```
from kedro.pipeline import Pipeline
Pipeline?

Init signature:
Pipeline(
    nodes: Iterable[Union[kedro.pipeline.node.Node, ForwardRef('Pipeline')]],
    *,
    tags: Union[str, Iterable[str]] = None,
)
Docstring:
A ``Pipeline`` defined as a collection of ``Node`` objects. This class
treats nodes as part of a graph representation and provides inputs,
outputs and execution order.
Init docstring:
Initialise ``Pipeline`` with a list of ``Node`` instances.

Args:
    nodes: The iterable of nodes the ``Pipeline`` will be made of. If you
        provide pipelines among the list of nodes, those pipelines will
        be expanded and all their nodes will become part of this
        new pipeline.
    tags: Optional set of tags to be applied to all the pipeline nodes.

Raises:
    ValueError:
        When an empty list of nodes is provided, or when not all
        nodes have unique names.
    CircularDependencyError:
        When visiting all the nodes is not
        possible due to the existence of a circular dependency.
:
```

Note This does jump you into a pager, a j,k or up, down to navigate, q to quit.

??sourcecode
────────────

Docstring not enough for you use case. I often run into cases where the docstring is not clear enough and I need to see the implementation for myself to see what a function does.

%run
────

I turned my nose up at this one, prior to seeing the famous I don’t like notebooks <https://www.youtube.com/watch?v=7jiPeIFXb6U> by Joel Grus <https://joelgrus.com/>. My first snobby reaction was that developing modules and using autoreload was superior. I have since realized there is a place for %run, and it can cut down on some keystrokes to import, setup, and run even when developing in modules.

%debug
──────

ipython comes with a post-mortem debugger, and it can be a lifesaver. If we have a long running function that runs into an error it can be a complete buzzkill.

```
def long_func():
   import time
   time.sleep(12)
   n = 12
   df = pd.Data({'a': range(n)})
   return df

long_func()
```

%reset
──────

Reclaim memory usage in Jupyter </reset-ipython/>

%autoreload
───────────

Autoreload in Ipython </autoreload-ipython/>

```
c.InteractiveShellApp.extensions = ["autoreload"]
c.InteractiveShellApp.exec_lines = ["%autoreload 2"]
c.InteractiveShellApp.exec_lines.append(
    'print("Warning: disable autoreload in ipython_config.py to improve performance.")'
)
```

│ place this in your ~/.ipython/profile_default/ipython_config.py to auto reload without needing to run the magic every time

autoformat
──────────

This is a relatively new feature to ipython. I really enjoy it, as the time that I need the most help autoformatting my code is riffing on an ad hoc analysis at the command line.

```
c.TerminalInteractiveShell.autoformatter = "black"
```

│ place this in your ~/.ipython/profile_default/ipython_config.py to autoformat with black by default

new prompt
──────────

reverse history search
──────────────────────

Control R

Want automatic imports??
────────────────────────

Smoother Python with automatic imports | pyflyby </pyflyby/>

│ This article covers how I setup automatic imports in ipython