Python code and Jupyter notebooks#

Python execution via Python files#

Python code can be written in “.py” files, which can be executed from the command line. We can do this with the simple file 01a_hello.py in this folder. Execute it in the terminal via python 01a_hello.py.

Python execution via Jupyter Notebooks#

Furthermore, for academic purposes, Jupyter notebooks are often used to run Python code, to document what the code does and add additional explanations and links to resources.

See also

Cell types#

Jupyter notebooks provide two types of cells:

  • Markdown cells for documentation, explanations, etc. (like this one)

  • Code cells to run Python code

To write our first small python program, we type in the Jupyter notebook code cell below. You can double-click in this cell, change the code and execute it by hitting CTRL+ENTER:

print("Hello world")

Hello world

Keyboard shortcuts#

  • When working with Jupyter notebooks, CTRL-ENTER or SHIFT-ENTER is the shortcut people use all the time.

  • If you want to “leave” a cell without executing it, you can also hit ESCAPE.

  • You can add a new cell above the current cell by hitting A and below by hitting B.

  • You can delete cells by hitting D.

There are more shortcuts. You can see them all in the menu above Help > Keyboard shortcuts or by hitting H.

Try it out!

Markdown documentation in Jupyter notebooks#

Markdown is a coding language for describing the formating of text. To see the Markdown code which describes this text, double-click this cell in your Jupyter notebook. Hit SHIFT+ENTER to return to the viewing mode.

  • Bullet point

  • More bullet points

    • Deeper bullet points

  1. List entry

  2. Another list entry

  3. More list entries

  4. Markdown cheatsheet

Exercise#

Add a new python code cell below and use the print command to print your name.