Here you can find answers to some of the most frequently asked questions 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 2017 uses Python 3.6.0 on the RoboRIO. When using pyfrc or similar projects, you should use a Python 3.5 or newer interpreter.
- RobotPy 2014.x is based on Python 3.2.5.
pynetworktables is compatible with Python 2.7 and 3.3 or newer
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.
Prior to 2015, the API matched the C++ version of WPILib.
Is Command-based programming available?¶
Is there an easy way to test my code outside of the robot?¶
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.
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 add SWIG wrappers to interface to it from Python (note, however, that this takes a fair amount of coding expertise).
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.
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!)