Here you can find answers to some of the most frequently asked questions about RobotPy.
Should our team use RobotPy?¶
What we often recommend teams to do is to take their existing code for their existing robot, and translate it to RobotPy and try it out first in the robot simulator, followed by the real robot. This will give you a good taste for what developing code for RobotPy will be like.
Related questions for those curious about RobotPy:
Installing and Running RobotPy¶
What version of Python do RobotPy projects use?¶
When running RobotPy on a FIRST Robot, our libraries/interpreters use Python 3. This means you should reference the Python 3.x documentation instead of the Python 2.x documentation.
RobotPy WPILib on the roboRIO uses the latest version of Python 3 at kickoff. In 2020, this was Python 3.8. When using pyfrc or similar projects, you should use a Python 3.6 or newer interpreter (the latest is recommended).
RobotPy 2014.x is based on Python 3.2.5.
pynetworktables is compatible with Python 3.5 or newer, since 2019. Releases prior to 2019 are also compatible with Python 2.7.
What happens when my code crashes?¶
An exception will be printed out to the console, and the Driver Station log may receive a message as well. It is highly recommended that you enable NetConsole for your robot, so you can see these messages.
Is WPILib available?¶
Of course! Just
import wpilib. Class and function names are identical
to the Java version. Check out the Python WPILib API Reference
for more details.
As of 2020, the API mostly matches the C++ version of WPILib, except that protected functions are prefixed with an underscore (but are availble to all Python code).
From 2015-2019, almost all classes and functions from the Java WPILib are available in RobotPy’s WPILib implementation.
Prior to 2015, the API matched the C++ version of WPILib.
Is Command-based programming available?¶
Of course! Check out the
command package. There
is also some python-specific documentation available.
Is RobotPy competition-legal?¶
As RobotPy was not written by anyone involved with the GDC, we can’t provide a guaranteed answer (particularly not for future years). However, we see no reason that RobotPy would not be legal: to the cRIO/RoboRIO, it looks just like any other C++ WPILib-using program that reads text files. RobotPy itself should be considered COTS software as it is freely available to all teams. Teams have been using RobotPy since 2010 without any problems from FIRST, and we expect that to continue.
Caveat emptor: while RobotPy is almost certainly legal to use, your team should carefully consider the risk of using such a large piece of unofficial software; unless RobotPy is used by many teams, if you run into trouble at a competition, there may not be anyone else there to help! However, we’ve found that most problems teams run into are problems with WPILib itself, and not RobotPy.
Also, be sure to keep in mind the fact that Python is a dynamic language and is NOT compiled. This means that typos can easily go undetected until your robot runs that particular line of code, resulting in an exception and 5 second restart. Make sure to test your code thoroughly (see our unit testing documentation).
Is RobotPy stable?¶
Yes! While Python is not an officially supported language, teams have been using RobotPy since 2010, and the maintainer of RobotPy is a member of the WPILib team. Much of the time when bugs are found, they are found in the underlying WPILib, instead of RobotPy itself.
One caveat to this is that because RobotPy doesn’t have a beta period like WPILib does, bugs tend to be found during the first half of competition season. However, by the time build season ends, RobotPy is just as stable as any of the officially suported languages.
How often does RobotPy get updated?¶
RobotPy is a community project, and updates are made whenever community members contribute changes and the developers decide to push a new release.
Historically, RobotPy tends to have frequent releases at the beginning of build season, with less frequent releases as build season goes on. We try hard to avoid WPILib releases after build season ends, unless critical bugs are found.
Is RobotPy fast?¶
It’s fast enough.
We’ve not yet benchmarked it, but it’s almost certainly just as fast as Java for typical WPILib-using robot code. RobotPy uses the native C++ WPILib, and thus the only interpreted portions are your specific robot actions. If you have particularly performance sensitive code, you can write it in C++ and use pybind11 wrappers to interface to it from Python.
Who created RobotPy?¶
RobotPy was created by Peter Johnson, programming mentor for FRC Team 294, Beach Cities Robotics. He was inspired by the Lua port for the cRIO created by Ross Light, FRC Team 973. Peter is a member of the FIRST WPILib team, and also created the ntcore and cscore libraries.
The current RobotPy maintainer is Dustin Spicuzza, also a member of the FIRST WPILib team.
Current RobotPy developers include:
How can I help?¶
RobotPy is an open project that all members of the FIRST community can easily and quickly contribute to. If you find a bug, or have an idea that you think others can use:
Test and report any issues you find.
Port and test a useful library.
Write a Python module and share it with others (and contribute it to the robotpy-wpilib-utilities package!)