EDS 217 Cheatsheet

Positron Basics: Variables Pane, Magic Commands, and Shortcuts

Sessions and interpreters

Starting a session

  1. Go to https://workbench-1.bren.ucsb.edu and log in.
  2. Click + New Session and choose Positron Pro.
  3. Allocate at least 2.5 GB of memory if the dialog asks.
  4. Click Launch.

Choosing where Python runs

Positron has two separate settings, and both need to read eds217_2026:

Setting Where it is What it controls
Interpreter Dropdown in the top right corner The Console
Kernel Kernel Selector in a notebook’s action bar That one notebook

Switching the interpreter shuts down the running one and starts the new one, so every variable you had defined is cleared. Choose it before you start working.

To change a notebook’s kernel from the keyboard, open the Command Palette (Ctrl + Shift + P or Cmd + Shift + P) and run Positron Notebook: Change Kernel.

Inspecting variables

The Variables pane

Positron shows your variables in the Variables pane on the right. Nothing needs to be installed, and the pane updates as you run cells. It shows:

  • Variable names
  • Types
  • Values and shapes
  • Length or count for collections
Code 
# Example variables
x = 5
y = "Hello"
z = [1, 2, 3]

# These appear in the Variables pane

The Data Explorer

Click a DataFrame in the Variables pane to open it in the Data Explorer, a sortable and filterable table view. This is the fastest way to look at a dataset you have just loaded.

Limits of the Variables pane

The Variables pane is not suitable for very large DataFrames or arrays. Use the standard commands df.head(), df.tail(), df.info(), and df.describe() to inspect large DataFrames.

Essential Magic Commands

Magic commands start with % (line magics) or %% (cell magics). They come from IPython, which is the Python kernel your notebooks run on, so they work in any editor that runs notebooks. Available magic commands vary with your environment and installed extensions.

Viewing Variables

Code 
# List all variables with type and value
%whos

# List just variable names
%who
Variable     Type        Data/Info
----------------------------------
ojs_define   function    <function ojs_define at 0x1aa1e23e0>
x            int         5
y            str         Hello
z            list        n=3
ojs_define   x   y   z

Running Shell Commands

Code 
# Run a shell command
!echo "Hello from the shell!"

# Capture output in a variable
files = !ls
print(files)
Hello from the shell!
['bar_plots.qmd', 'chart_customization.qmd', 'comprehensions.qmd', 'control_flows.qmd', 'data_cleaning.qmd', 'data_grouping.qmd', 'data_merging.qmd', 'data_selection.qmd', 'dictionaries.qmd', 'first_steps.qmd', 'functions.qmd', 'lists.qmd', 'matplotlib_cheatsheet.pdf', 'matplotlib.qmd', 'numpy.qmd', 'Pandas_Cheat_Sheet.pdf', 'pandas_dataframes.qmd', 'pandas_series.qmd', 'positron.qmd', 'positron.quarto_ipynb', 'print.qmd', 'read_csv.qmd', 'seaborn.qmd', 'sets.qmd', 'setting_up_python.qmd', 'timeseries.qmd', 'workflow_methods.qmd']

Useful Keyboard Shortcuts

Positron’s shortcuts are, with a few exceptions, a superset of the Visual Studio Code shortcuts.

Notebooks

Action Windows/Linux Mac
Run cell and select below Shift + Enter Shift + Enter
Run cell and stay put Ctrl + Enter Cmd + Enter
Save notebook Ctrl + S Cmd + S
Command Palette Ctrl + Shift + P Cmd + Shift + P

Editor and Console

Action Windows/Linux Mac
Run the current line or selection Ctrl + Enter Cmd + Enter
Contextual help for the name under the cursor F1 F1
Clear the Console Ctrl + L Ctrl + L
Command Palette Ctrl + Shift + P Cmd + Shift + P

Every command Positron knows is in the Command Palette, and the palette shows the shortcut next to each command. When you cannot remember a shortcut, search the palette for the action by name.

Tips for Beginners

  1. Use Tab for code completion.
  2. Add ? after a function name for more detailed help (for example, print?).
  3. Press F1 with your cursor on a name to open its documentation in the Help pane.
  4. Use dir() to see available attributes and methods (for example, dir(str)).
  5. Use the help() command to get information about functions and objects.
  6. Restart the kernel from the notebook action bar when things stop making sense, then re-run your cells from the top.

Resources for Further Learning