[Question] There is no Box2D even though I pip installed gym

[fehimornek]

I am having trouble in a very simple task.
I am trying to run CarRacing environment with the following code

import gym
env = gym.make("CarRacing-v1")
env.reset()

and it throws an error
AttributeError: module 'gym.envs.box2d' has no attribute 'CarRacing'
I tried to run another code that was proposed in another issue #2786 like this

from gym.envs.box2d.car_racing import CarRacing
env = CarRacing()
env.reset()

but this time got the error
ModuleNotFoundError: No module named 'Box2D'

When I try to download Box2D with

pip install gym[box2d]

it says
error: legacy-install-failure

and I searched online but solutions for gym doesnt really exist.

Thanks in advance.

[pseudo-rnd-thoughts]

I have never seen this error before
Could you run pip uninstall gym and pip install gym[box2d]
If this fail, could you give us the full install error message plus your operating system, the python version and the gym version that it tries to install.

[sidney-tio]

Hey both, I encountered the same problem trying to create LunarLander as well. It seems that the problem resides with Box2D and the related try statement that leaves the problem undetected at

gym/gym/envs/box2d/__init__.py

Lines 1 to 2 in 95063a0

	try:
	import Box2D

When I tried pip install gym[box2d], it also resulted in same problems: error: legacy-install-failure.

I got around the problem by installing Box2D manually with pip install box2d pygame, and it works now.

@pseudo-rnd-thoughts: I noticed that gym's setup.py uses a deprecated version of Box2D (box2d-py). Perhaps the team would like to consider updating it to Box2D instead? https://pypi.org/project/Box2D/

[sidney-tio]

adding on: perhaps it would be useful to raise an error message when importing Box2D causes ImportErrors to help with debugging.

[pseudo-rnd-thoughts]

@sidney-tio Thanks for the comment, I had never seen that try and except and will see if I can remove that
Investigating the box2d-py install, this seems to be a legacy produce of gym where OpenAI forked an old repo of box2d as the install from pip

I will investigate moving to the more recent box2d as a temporary solution as we planning on moving to brax which should improve performance for the environments however this could be a few months out at

[fehimornek]

Hi again, I tried both of the solutions and they didn't work, here are the error messages:

1. solution
pip uninstall gym
pip install gym[box2d]

Collecting gym[box2d]
Using cached gym-0.23.1-py3-none-any.whl
Requirement already satisfied: numpy>=1.18.0 in c:\users\fehim\pycharmprojects\cybernetics\venv\lib\site-packages (from gym[box2d]) (1.22.2)
Requirement already satisfied: cloudpickle>=1.2.0 in c:\users\fehim\pycharmprojects\cybernetics\venv\lib\site-packages (from gym[box2d]) (2.0.0)
Requirement already satisfied: importlib-metadata>=4.10.0 in c:\users\fehim\pycharmprojects\cybernetics\venv\lib\site-packages (from gym[box2d]) (4.11.3)
Requirement already satisfied: gym-notices>=0.0.4 in c:\users\fehim\pycharmprojects\cybernetics\venv\lib\site-packages (from gym[box2d]) (0.0.6)
Collecting box2d-py==2.3.5
Using cached box2d-py-2.3.5.tar.gz (374 kB)
Preparing metadata (setup.py) ... done
Collecting pygame==2.1.0
Using cached pygame-2.1.0-cp39-cp39-win_amd64.whl (4.8 MB)
Requirement already satisfied: zipp>=0.5 in c:\users\fehim\pycharmprojects\cybernetics\venv\lib\site-packages (from importlib-metadata>=4.10.0->gym[box2d]) (3.8.0)
Building wheels for collected packages: box2d-py
Building wheel for box2d-py (setup.py) ... error
error: subprocess-exited-with-error

× python setup.py bdist_wheel did not run successfully.
│ exit code: 1
╰─> [16 lines of output]
Using setuptools (version 57.0.0).
running bdist_wheel
running build
running build_py
creating build
creating build\lib.win-amd64-3.9
creating build\lib.win-amd64-3.9\Box2D
copying library\Box2D\Box2D.py -> build\lib.win-amd64-3.9\Box2D
copying library\Box2D_init_.py -> build\lib.win-amd64-3.9\Box2D
creating build\lib.win-amd64-3.9\Box2D\b2
copying library\Box2D\b2_init_.py -> build\lib.win-amd64-3.9\Box2D\b2
running build_ext
building 'Box2D._Box2D' extension
swigging Box2D\Box2D.i to Box2D\Box2D_wrap.cpp
swig.exe -python -c++ -IBox2D -small -O -includeall -ignoremissing -w201 -globals b2Globals -outdir library\Box2D -keyword -w511 -D_SWIG_KWARGS -o Box2D\Box2D_wrap.cpp Box2D\Box2D.i
error: command 'swig.exe' failed: None
[end of output]

note: This error originates from a subprocess, and is likely not a problem with pip.
ERROR: Failed building wheel for box2d-py
Running setup.py clean for box2d-py
Failed to build box2d-py
Installing collected packages: box2d-py, pygame, gym
Running setup.py install for box2d-py ... error
error: subprocess-exited-with-error

× Running setup.py install for box2d-py did not run successfully.
│ exit code: 1
╰─> [16 lines of output]
Using setuptools (version 57.0.0).
running install
running build
running build_py
creating build
creating build\lib.win-amd64-3.9
[end of output]

note: This error originates from a subprocess, and is likely not a problem with pip.
error: legacy-install-failure

× Encountered error while trying to install package.
╰─> box2d-py

note: This is an issue with the package mentioned above, not pip.
hint: See above for output from the failure.

2. solution
pip install gym[box2d] pygame

Collecting box2d
Using cached Box2D-2.3.2.tar.gz (427 kB)
Preparing metadata (setup.py) ... done
Requirement already satisfied: pygame in c:\users\fehim\pycharmprojects\cybernetics\venv\lib\site-packages (2.1.2)
Building wheels for collected packages: box2d
Building wheel for box2d (setup.py) ... error
error: subprocess-exited-with-error

× python setup.py bdist_wheel did not run successfully.
│ exit code: 1
╰─> [16 lines of output]
Using setuptools (version 57.0.0).
running bdist_wheel
running build
running build_py
creating build
creating build\lib.win-amd64-3.9
creating build\lib.win-amd64-3.9\Box2D
copying library\Box2D\Box2D.py -> build\lib.win-amd64-3.9\Box2D
copying library\Box2D_init_.py -> build\lib.win-amd64-3.9\Box2D
creating build\lib.win-amd64-3.9\Box2D\b2
copying library\Box2D\b2_init_.py -> build\lib.win-amd64-3.9\Box2D\b2
running build_ext
building 'Box2D._Box2D' extension
swigging Box2D\Box2D.i to Box2D\Box2D_wrap.cpp
swig.exe -python -c++ -IBox2D -small -O -includeall -ignoremissing -w201 -globals b2Globals -outdir library\Box2D -keyword -w511 -D_SWIG_KWARGS -o Box2D\Box2D_wrap.cpp Box2D\Box2D.i
error: command 'swig.exe' failed: None
[end of output]

note: This error originates from a subprocess, and is likely not a problem with pip.
ERROR: Failed building wheel for box2d
Running setup.py clean for box2d
Failed to build box2d
Installing collected packages: box2d
Running setup.py install for box2d ... error
error: subprocess-exited-with-error

× Running setup.py install for box2d did not run successfully.
│ exit code: 1
╰─> [16 lines of output]
Using setuptools (version 57.0.0).
running install
running build
running build_py
creating build
creating build\lib.win-amd64-3.9
creating build\lib.win-amd64-3.9\Box2D
copying library\Box2D\Box2D.py -> build\lib.win-amd64-3.9\Box2D
copying library\Box2D_init_.py -> build\lib.win-amd64-3.9\Box2D
creating build\lib.win-amd64-3.9\Box2D\b2
copying library\Box2D\b2_init_.py -> build\lib.win-amd64-3.9\Box2D\b2
running build_ext
building 'Box2D._Box2D' extension
swigging Box2D\Box2D.i to Box2D\Box2D_wrap.cpp
swig.exe -python -c++ -IBox2D -small -O -includeall -ignoremissing -w201 -globals b2Globals -outdir library\Box2D -keyword -w511 -D_SWIG_KWARGS -o Box2D\Box2D_wrap.cpp Box2D\Box2D.i
error: command 'swig.exe' failed: None
[end of output]

note: This error originates from a subprocess, and is likely not a problem with pip.
error: legacy-install-failure

× Encountered error while trying to install package.
╰─> box2d

note: This is an issue with the package mentioned above, not pip.
hint: See above for output from the failure.

Sorry for the late reply

[pseudo-rnd-thoughts]

The error was caused by swig error: command 'swig.exe' failed: None
You can download swig here
This should fix your issue.

[sidney-tio]

if install swig doesnt work, try installing box2d manually (i.e. pip install box2d (instead of gym[box2d])? see my reply above:

Hey both, I encountered the same problem trying to create LunarLander as well. It seems that the problem resides with Box2D and the related try statement that leaves the problem undetected at

gym/gym/envs/box2d/__init__.py

Lines 1 to 2 in 95063a0

	try:
	import Box2D

When I tried pip install gym[box2d], it also resulted in same problems: error: legacy-install-failure.

I got around the problem by installing Box2D manually with pip install box2d pygame, and it works now.

[fehimornek]

After downloading swig I also had to

pip3 install box2d box2d-kengz

Solved the issue

But I don't understand why doing such a menial task required this many steps, what was the problem here me or the gym library?

[pseudo-rnd-thoughts]

So box2d is different from box2d-py that gym uses. You should just need to install swig (which is a requirement of box2d) and then run pip install gym[box2d]

[Ashfaqe-oss]

how am I supposed to install swig after downloading it ?

[jjshoots]

@Ashfaqe-oss In Ubuntu it should just be sudo apt install swig, on MacOS it should be sudo brew install swig, we don't have official Windows support.

[kbbbhhy]

Thanks. It works.

[TernaryM01]

I've tried installing swig first:
sudo apt install swig
And only then install box2d:
pip install gymnasium
pip install gymnasium[box2d]
It succeeded without any error or warning.

[Louis1234567890]

When I uninstalled swig and reinstalled it I got

WARNING: The script swig.exe is installed in 'C:[...]\Scripts' which is not on PATH.
Consider adding this directory to PATH or, if you prefer to suppress this warning, use --no-warn-script-location.

Might this explain the (error: command 'swig.exe' failed: None) when installing gym[box2d] ?

[jjshoots]

@Louis1234567890, possibly, SWIG is a parser for Cpp to Python, so things could fail if that's not on PATH. That said, I've never developed code in Windows so I wouldn't know.

[leiquan]

After downloading swig I also had to

pip3 install box2d box2d-kengz

Solved the issue

But I don't understand why doing such a menial task required this many steps, what was the problem here me or the gym library?

thank you, it helps me

[wsxyh107165243]

After downloading swig I also had to

pip3 install box2d box2d-kengz

Solved the issue

But I don't understand why doing such a menial task required this many steps, what was the problem here me or the gym library?

Thanks, this helped me.

[khan008]

EveryOne, Instead of box2d install pip install pygame to get rid of this headache. Hope problem answered successfuly

[Akram-Ashyani]

Hey both, I encountered the same problem trying to create LunarLander as well. It seems that the problem resides with Box2D and the related try statement that leaves the problem undetected at

gym/gym/envs/box2d/__init__.py

Lines 1 to 2 in 95063a0

	try:
	import Box2D

When I tried pip install gym[box2d], it also resulted in same problems: error: legacy-install-failure.

I got around the problem by installing Box2D manually with pip install box2d pygame, and it works now.

@pseudo-rnd-thoughts: I noticed that gym's setup.py uses a deprecated version of Box2D (box2d-py). Perhaps the team would like to consider updating it to Box2D instead? https://pypi.org/project/Box2D/

Thank you immensely. Your solution was helpful and resolved my issue.

[AsteroidHunter]

If you ended up here because of the following error: zsh: no matches found: gymnasium[box2d]
Try pip install 'gymnasium[box2d]'

Basically, Z shell interprets the square brackets as a pattern matching expression, and searches for files named "b" or "o" or "x" and so on. Enclosing it with quotations (' ') makes Zsh treat everything inside as a single string without any special characters.

[danialzendehdel]

If you ended up here because of the following error: zsh: no matches found: gymnasium[box2d] Try pip install 'gymnasium[box2d]'

Basically, Z shell interprets the square brackets as a pattern matching expression, and searches for files named "b" or "o" or "x" and so on. Enclosing it with quotations (' ') makes Zsh treat everything inside as a single string without any special characters.

This solved my problem

[AbogAscended]

If you ended up here because of the following error: zsh: no matches found: gymnasium[box2d] Try pip install 'gymnasium[box2d]'

Basically, Z shell interprets the square brackets as a pattern matching expression, and searches for files named "b" or "o" or "x" and so on. Enclosing it with quotations (' ') makes Zsh treat everything inside as a single string without any special characters.

I could kiss you