--- hide-toc: true firstpage: lastpage: --- ```{project-logo} _static/img/gymnasium-text.png :alt: Gymnasium Logo ``` ```{project-heading} An API standard for reinforcement learning with a diverse collection of reference environments ``` ```{figure} _static/videos/box2d/lunar_lander.gif :alt: Lunar Lander :width: 500 ``` **Gymnasium is a maintained fork of OpenAI’s Gym library.** The Gymnasium interface is simple, pythonic, and capable of representing general RL problems, and has a [compatibility wrapper](introduction/gym_compatibility) for old Gym environments: ```{code-block} python import gymnasium as gym # Initialise the environment env = gym.make("LunarLander-v3", render_mode="human") # Reset the environment to generate the first observation observation, info = env.reset(seed=42) for _ in range(1000): # this is where you would insert your policy action = env.action_space.sample() # step (transition) through the environment with the action # receiving the next observation, reward and if the episode has terminated or truncated observation, reward, terminated, truncated, info = env.step(action) # If the episode has ended then we can reset to start a new episode if terminated or truncated: observation, info = env.reset() env.close() ``` ```{toctree} :hidden: :caption: Introduction introduction/basic_usage introduction/train_agent introduction/create_custom_env introduction/record_agent introduction/speed_up_env introduction/gym_compatibility introduction/migration_guide ``` ```{toctree} :hidden: :caption: API api/env api/registry api/spaces api/wrappers api/vector api/utils api/functional ``` ```{toctree} :hidden: :caption: Environments environments/classic_control environments/box2d environments/toy_text environments/mujoco environments/atari environments/third_party_environments ``` ```{toctree} :hidden: :glob: :caption: Tutorials tutorials/**/index tutorials/third-party-tutorials ``` ```{toctree} :hidden: :caption: Development Github Paper gymnasium_release_notes/index gym_release_notes/index Contribute to the Docs ```