0.2 Python & Jupyter Basics

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0.2 Python & Jupyter Basics#

Tutorials at the 2025 paleoCAMP | June 16–June 30, 2025

Jiang Zhu
jiangzhu@ucar.edu
Climate & Global Dynamics Laboratory
NSF National Center for Atmospheric Research

Why Python?#

  • Python is open source.

  • Python is a high-productivity language: do more with less code.

  • Python is interpreted and portable, like Matlab, so no need to compile your code for it to run.

  • Python is highly human readable and popular. Currently there are 600,000+ Python packages on the Python Package Index (PyPI).

“How to install external Python libs on my laptop / desktop?”#

To best way to get the scientific Python environment is using the Conda package management system. Please follow the official installation guide for installing on

Hello world#

print("Hello world!")

Hello world!

Comparison between Python, C, and Matlab#

  • Python uses 0 based ordering

  • Python uses # sign for commenting

  • Python determines block size based on indentation, i.e., no end or } to close a block

Python vs C vs Matlab

Figure: Python vs C vs Matlab

Jupyter#

Jupyter is a web server for interactive computing that supports multiple programming languages.

When you run it on your laptop (Jupyter Notebook or JupyterLab), you can directly interact with the web server from your browser.
When working remotely (e.g., on a HPC), you just communicate HTML (and serialized data) back and forth from your browser to the web server.

Reproducibility & Extensibility#

It is fast and efficient.
Jupyter allows you to save your work in a notebook (ipynb), so you can share your work with other people simply by sharing your notebook file. Other people can use it and extend it for their own purposes.

A Jupyter Notebook is composed of cells. A Cell could have three types#

  • Code cell contains Python code

  • Markdown cell has Markup language and can be used for notes/comments

  • Raw cell has simple text

jupyterhub_cell_types

Figure: Cell types

How to run a cell?#

To run a cell in a notebook. Click on the cell and press: Shift+return

Running a cell

Figure: Running a cell

How to run a shell command within a cell?#

# list the content of within the current directory

!ls

0.1_demo_unix.ipynb			 7_run_challenging_LGM.ipynb
0.2_intro_python_jupyter.ipynb		 _build
0.3_demo_ncar_account_jupyterhub.ipynb	 _config.yml
1_intro_to_CESM.ipynb			 images
2_demo_run_CESM_4steps.ipynb		 intro.md
3_analyze_CESM_output.ipynb		 LICENSE
4a_opt1_run_piControl_midHolocene.ipynb  precip_xy.era5.png
4b_opt2_analyze_long_midHolocene.ipynb	 README.md
5_info_Data_Access.ipynb		 _toc.yml
6_info_iCESM_iTRACE.ipynb

%ls

0.1_demo_unix.ipynb                      7_run_challenging_LGM.ipynb
0.2_intro_python_jupyter.ipynb           _build/
0.3_demo_ncar_account_jupyterhub.ipynb   _config.yml
1_intro_to_CESM.ipynb                    images/
2_demo_run_CESM_4steps.ipynb             intro.md
3_analyze_CESM_output.ipynb              LICENSE
4a_opt1_run_piControl_midHolocene.ipynb  precip_xy.era5.png
4b_opt2_analyze_long_midHolocene.ipynb   README.md
5_info_Data_Access.ipynb                 _toc.yml
6_info_iCESM_iTRACE.ipynb

More learning resources (optional)#

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