Getting started example causes TypeError: object of type 'TimeLimit' has no len()

[SorenSc]

• [x] I have marked all applicable categories:
  • [x] exception-raising bug
  • [ ] RL algorithm bug
  • [ ] documentation request (i.e. "X is missing from the documentation.")
  • [ ] new feature request
• [x] I have visited the source website
• [x] I have searched through the issue tracker for duplicates
• [ ] I have mentioned version numbers, operating system and environment, where applicable:

  import tianshou, gym, torch, numpy, sys
  print(tianshou.__version__, gym.__version__, torch.__version__, numpy.__version__, sys.version, sys.platform)
  # 0.4.11 0.26.2 1.13.1 1.23.5 3.10.9 (main, Mar  1 2023, 12:20:14) [Clang 14.0.6 ] darwin
  # I'm using gymnasium (import gymnasium as gym)
  # I'm running it on an Apple M1 Pro

  I'm tryin to execute the example on the start page (https://github.com/thu-ml/tianshou).

When running

  collector = ts.data.Collector(policy, env, exploration_noise=True)

I ran into the following

  ---------------------------------------------------------------------------
  TypeError                                 Traceback (most recent call last)
  Cell In[8], line 3
        1 policy.eval()
        2 policy.set_eps(eps_test)
  ----> 3 collector = ts.data.Collector(policy, env, exploration_noise=True)
        4 collector.collect(n_episode=1, render=1 / 35)  

  File ~/miniconda3/envs/rl-index/lib/python3.10/site-packages/tianshou/data/collector.py:72, in Collector.__init__(self, policy, env, buffer, preprocess_fn, exploration_noise)
       70 else:
       71     self.env = env  # type: ignore
  ---> 72 self.env_num = len(self.env)
       73 self.exploration_noise = exploration_noise
       74 self._assign_buffer(buffer)  

  TypeError: object of type 'TimeLimit' has no len()

When doing the same in GoogleColab, I'm having the same issue.

[Trinkle23897]

Thanks for reporting this issue, will fix soon!

[zzw1123]

I have the same issue when running DQN in CartPole-v0. Please stay in touch when you fix it! Thx.

[zzw1123]

Just change "import gym" to "import gymnasium as gym" in collector.py.

[Trinkle23897]

Update: I can't reproduce the above error. I think it's because of a version mismatch, since I ran with current master version instead of using tianshou==0.4.11. Will post a new version to pypi today.

[Amazingldl]

Update: I can't reproduce the above error. I think it's because of a version mismatch, since I ran with current master version instead of using tianshou==0.4.11. Will post a new version to pypi today.

Hello, @Trinkle23897 Thanks for the great work, but I am still getting this issue: Just copy the example-1 from https://tianshou.readthedocs.io/zh/latest/docs/5-example.html