Using Nu¶
Nu is a simple Python editor for people learning to code. This page is what opens when you click Help in Nu.
The buttons¶
These are always on the toolbar:
| Button | Does | Shortcut |
|---|---|---|
| Mode | Switch between modes (see below). | Ctrl+Shift+M |
| New | Open a new, empty tab. | Ctrl+N |
| Load | Open a file. | Ctrl+O |
| Save | Save the current tab. Nu also saves your work every few seconds once a file has a name. | Ctrl+S |
| Zoom-in / Zoom-out | Make the text bigger or smaller. | Ctrl++ / Ctrl+- |
| Theme | Switch between the day, night and high-contrast looks. | F1 |
| Check | Look for mistakes in your code and mark them in the margin. | F2 |
| Tidy | Neatly reformat your code. | F10 |
| Help | Open this page. | Ctrl+H |
| Quit | Close Nu. It asks first if you have unsaved work. | Ctrl+Q |
On a Mac, use Cmd instead of Ctrl.
Modes¶
Each mode adds its own buttons, between Save and Zoom-in.
Python 3¶
Write and run ordinary Python programs.
- Run (F5) runs your program. Its output, and anything it asks you to type in, appear in a pane below your code.
- Debug (F6) runs your program step by step. Click a line number first to add a breakpoint where it should pause.
- REPL (Ctrl+Shift+I) opens a prompt where you can type Python and see the result straight away.
- Plotter (Ctrl+Shift+P) draws a graph of numbers your program prints as
tuples, e.g.
print((temperature, humidity)).
Graphical Debugger¶
This mode opens when you click Debug. While your program is paused, the panel on the right shows its variables. Use Step Over (F10), Step In (F11) and Step Out (Shift+F11) to move through your code, Continue (F5) to run to the next breakpoint, and Stop (Shift+F5) to finish.
Pygame Zero¶
Make games with Pygame Zero.
- Play (F5) runs your game.
- Images, Fonts, Sounds and Music open the folders your game's pictures and sounds go in. Nu starts you off with a few examples.
CircuitPython¶
Write code for microcontroller boards running
CircuitPython. Plug your board in and save your
code as code.py on the board's CIRCUITPY drive; it runs every time you
save.
- Serial (Ctrl+Shift+U) shows what your board prints, and lets you type to it. Press Ctrl+C there to get a REPL on the board.
- Plotter (Ctrl+Shift+P) graphs tuples your board prints.
Where your files go¶
Nu saves your work in a folder called mu_code in your home folder (the name
comes from Mu, the editor Nu continues). It's what Load and Save show
first.
Adding Python packages¶
Your programs run in their own Python environment, separate from Nu. To use a
package such as requests, click the cog in the bottom-right corner, open
Third Party Packages, put the package's name on its own line, and click
OK. The cog also has Nu's log, environment variables, and the language
setting.
Plugins¶
Plugins add new modes to Nu. To try one, put its .py file (or folder) in
Nu's plugins folder and restart Nu:
| System | Plugins folder |
|---|---|
| Windows | %LOCALAPPDATA%\python\mu\plugins |
| macOS | ~/Library/Application Support/mu/plugins |
| Linux | ~/.local/share/mu/plugins |
Plugins are Python code that runs inside Nu, so only add ones you trust. If a plugin has a problem, Nu tells you and keeps running. To write one, see Writing a Nu plugin.
Something went wrong?¶
- Nu crashed: it shows the details of what went wrong. Click Copy to clipboard and paste them into a report (below). Nu never sends anything anywhere by itself.
- Report a problem or suggest an idea at github.com/kovirlabs/nu/issues.
- Learn more: the original Mu's tutorials still apply to most of Nu, though Nu no longer has the micro:bit, ESP, Pico or web modes.