Python for data analysis: Overview of Jupyter Notebooks

Screenshot of a Jupyter Notebook on quantum mechanics by Robert Johansson

How the Jupyter notebook works

After typing the command jupyter notebook, the following happens:

• A Jupyter Notebook server is automatically created on your local machine.
• The Jupyter Notebook server runs locally on your machine only and does not use an internet connection.

• The Jupyter Notebook server opens the Jupyter notebook client, also known as the notebook user interface, in your default web browser.

  The Jupyter notebook file browser

• To create a new Python notebook select the “New” dropdown on the upper right of the screen.

  The Jupyter notebook file browser

• When you can create a new notebook and type code into the browser, the web browser and the Jupyter notebook server communicate with each other.

  A new, blank Jupyter notebook

• Under the “help” menu, take a quick interactive tour of how to use the notebook. Help on Jupyter and key workshop packages is available here too.

  User interface tour and Help

• The Jupyter Notebook server does the work and calculations, and the web browser renders the notebook.

• The web browser then displays the updated notebook to you.

• For example, click in the first cell and type some Python code.

  A Code cell

• This is a Code cell (see the cell type dropdown with the word Code). To run the cell, type Shift+Return.

  A Code cell and its output

• Let’s look at a Markdown cell. Markdown is a text manipulation language that is readable yet offers additional formatting. Don’t forget to select Markdown from the cell type dropdown. Click in the cell and enter the markdown text.

  A markdown input cell

• To run the cell, type Shift+Return.

  A rendered markdown cell

This workflow has several advantages:

• You can easily type, edit, and copy and paste blocks of code.
• Tab completion allows you to easily access the names of things you are using and learn more about them.
• It allows you to annotate your code with links, different sized text, bullets, etc. to make information more accessible to you and your collaborators.
• It allows you to display figures next to the code that produces them to tell a complete story of the analysis.

How the notebook is stored

• The notebook file is stored in a format called JSON and has the suffix .ipynb.
• Just like HTML for a webpage, what’s saved in a notebook file looks different from what you see in your browser.
• But this format allows Jupyter to mix software (in several languages) with documentation and graphics, all in one file.

Notebook modes: Control and Edit

The notebook has two modes of operation: Control and Edit. Control mode lets you edit notebook level features; while, Edit mode lets you change the contents of a notebook cell. Remember a notebook is made up of a number of cells which can contain code, markdown, html, visualizations, and more.

Help and more information

Use the Help menu and its options when needed.