title: What's the different between these two results?
body: <p>Here is my code:</p>
  
  <pre><code>import gym
  
  env = gym.make("CartPole-v1")
  
  print (env.observation_space.shape)
  print (env.observation_space.shape[0])
  </code></pre>
  
  <p>The result is</p>
  
  <pre><code>(4,)
  4
  </code></pre>
  
  <p>I don't understand what's the difference between (4,) and 4 ?</p>