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问题：Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "/home/tofugan/gym/gym/envs/registration.py", line 167, in make
return registry.make(id)
File "/home/tofugan/gym/gym/envs/registration.py", line 125, in make
patch_deprecated_methods(env)
File "/home/tofugan/gym/gym/envs/registration.py", line 185, in patch_deprecated_methods
env.seed = env._seed
AttributeError: 'GridEnv' object has no attribute '_seed'
问题分析：
在registration.py文件中找到如下代码：
env.reset = env._reset
env.step = env._step
env.seed = env._seed
对比其他的模型（如：CartPole-v0）我们发现书中的代码不存在seed函数。
解决方法：
1、注释掉（不推荐）
#env.seed = env._seed
之所以不推荐是因为其他模型会用到这个，每次都要改很麻烦。
env = gym.make('GridWorld-v0')
WARN: Environment '<class 'gym.envs.classic_control.grid_mdp.GridEnv'>' has deprecated methods '_step' and '_reset' rather than 'step' and 'reset'. Compatibility code invoked. Set _gym_disable_underscore_compat = True to disable this behavior.
可以忽略
出现新的问题：
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "/home/tofugan/gym/gym/core.py", line 275, in render
return self.env.render(mode, **kwargs)
File "/home/tofugan/gym/gym/envs/registration.py", line 187, in render
return env._render(mode, close=False)
AttributeError: 'GridEnv' object has no attribute '_render'
根据提示将render改为_render即可
结果：
2、添加_seed方法
取消前面的注释
添加
def _seed(self, seed=None):
self.np_random, seed = seeding.np_random(seed)
return [seed]
结果：