This page was generated from `/home/lectures/exp3/source/notebooks/Intro/NotebookEditor.ipynb`_.

Notebook editor

A Jupyter Notebook provides an interface with essentially two modes

• edit mode the mode where you edit a cell’s content.

• command mode the mode where you execute the cells content.

In the more advanced version of JupyterLab, which we are using on myBinder, this will look like that

Edit mode

Edit mode is indicated by a blue cell border and a prompt showing in the editor area:

When a cell is in edit mode, you can type into the cell, like a normal text editor.

Command mode

Command mode is indicated by a grey cell border:

Keyboard navigation

If you have a hardware keyboard connected to your iOS device, you can use Jupyter keyboard shortcuts. The modal user interface of the Jupyter Notebook has been optimized for efficient keyboard usage. This is made possible by having two different sets of keyboard shortcuts: one set that is active in edit mode and another in command mode.

In edit mode, most of the keyboard is dedicated to typing into the cell’s editor. Thus, in edit mode there are relatively few shortcuts. In command mode, the entire keyboard is available for shortcuts, so there are many more. Most important ones are:

1. Switch command and edit mods: Enter for edit mode, and Esc or Control for command mode.

2. Basic navigation: ↑/k, ↓/j

3. Run or render currently selected cell: Shift+Enter or Control+Enter

4. Saving the notebook: s

5. Change cell types: y to make it a code cell, m for markdown and r for raw

6. Inserting new cells: a to insert above, b to insert below

7. Manipulating cells using pasteboard: x for cut, c for copy, v for paste, d for delete and z for undo delete

8. Kernel operations: i to interrupt and 0 to restart

Running code

Code cells allow you to enter and run code. Run a code cell by pressing the ▶︎ button in the bottom-right panel, or Control+Enter on your hardware keyboard.

v = 10

print(v)

100

There are a couple of keyboard shortcuts for running code:

• Control+Enter runs the current cell and enters command mode.

• Shift+Enter runs the current cell and moves selection to the one below.

• Option+Enter runs the current cell and inserts a new one below.

Managing the kernel

Code is run in a separate process called the kernel, which can be interrupted or restarted. You can see the kernel indicator in the top-right corner reporting the current kernel state: ⚪︎ means the kernel is ready to execute code, and ⚫︎ means the kernel is currently busy. Tapping kernel indicator will open the kernel menu, where you can reconnect, interrupt or restart the kernel.

Try running the following cell — kernel indicator will switch from ⚪︎ to ⚫︎, i.e., reporting the kernel as “busy”. This means that you will not be able to run any new cells until the current execution finishes, or until the kernel is interrupted. You can then go to the kernel menu by tapping the kernel indicator and select “Interrupt”.