How do I change the autoindent to 2 space in IPython notebook

Question

I find that developing functions in IPython notebook allows me to work quickly. When I'm happy with the results I copy-paste to a file. The autoindent is 4 spaces, but the coding style for indentation at my company is 2 spaces. How do I change the autoindent to 2 spaces?

Answer 1

Based on this question and the options found here:
In your custom.js file (location depends on your OS) put

IPython.Cell.options_default.cm_config.indentUnit = 2;

On my machine the file is located in ~/.ipython/profile_default/static/custom

Update:

In IPython 3 the plain call does not work any more, thus it is required to place the setting within an appropriate event handler. A possible solution could look like

define([
    'base/js/namespace',
    'base/js/events'
    ],
    function(IPython, events) {
        events.on("app_initialized.NotebookApp",
            function () {
                IPython.Cell.options_default.cm_config.indentUnit = 2;
            }
        );
    }
);

Answer 2

The official documentation has an example answering this specific question. This worked for me with IPython 4.

Summary: Paste the following into your browser's javascript console

var cell = Jupyter.notebook.get_selected_cell();
var config = cell.config;
var patch = {
      CodeCell:{
        cm_config:{indentUnit:2}
      }
    }
config.update(patch)

The setting is persisted. You can roll back by exchanging : 2 for : null.

Answer 3

From the official documentation for CodeMirror Code Cells:

1. Open an Ipython Notebook
2. Create a Code Cell e.g. by pressing b
3. Open your browser’s JavaScript console and run the following

snippet:

var cell = Jupyter.notebook.get_selected_cell();
var config = cell.config;
var patch = {
      CodeCell:{
        cm_config:{indentUnit:2}
      }
    }
config.update(patch)

4. Reload the notebook page in the browser e.g. by pressing F5

This will fix it permanently. I assume this works only on recent versions, not sure though!

Answer 4

AdamAL's answer is correct. It worked for me.

However it only changes the indentation in the Jupyter Notebook and leaves the indentation in the Jupyter Editor unaffected.

A more direct way to change the indentation is to directly edit the Jupyter config files in the .jupyter/nbconfig directory. This directory contains 2 files:

edit.json
notebook.json

The option you must set in either one is indentUnit. Here is the content of my Jupyter config files:

edit.json:

{
  "Editor": {
    "codemirror_options": {
      "indentUnit": 2,
      "vimMode": false, 
      "keyMap": "default"
    }
  }
}

notebook.json:

{
  "CodeCell": {
    "cm_config": {
      "indentUnit": 2
    }
  }
}

With this approach I've set the default indentation to 2 in both the Jupyter Notebook and the Jupyter Editor.

Answer 5

I believe this is now best wrapped in a event handler to load once per notebook load:

$([IPython.events]).on('app_initialized.NotebookApp', function(){
  IPython.CodeCell.options_default['cm_config']['indentUnit'] = 2;
});

Answer 6

In addition to adding

IPython.Cell.options_default.cm_config.indentUnit = 2;

to your custom.js file as suggested by Jakob, be sure to clear your browser cache as well before restarting ipython notebook!

Also, you may have to first create the ~/.config/ipython/profile_default/static/custom/ directory (use echo $(ipython locate default) to find your default directory) before adding the custom.js file.

Answer 7

If you use jupyterlab, there seems to be an easier way:

1) Click jupyterlab menu Settings > Advanced Setting Editor

2) Click "Notebook" on the left hand pane, make sure you are on "Raw View"

3) On the right pane, under "User Overrides", enter this:

{
    "codeCellConfig": {
        "tabSize": 2
    }
}

If you look at the System Defaults, that will give you hint on whats overridable and you can repeat this for other settings.

I tried this on Google Platform AI Notebook which uses Jupyterlab.