title: Conda: packages are already installed by pip but not shown in conda list
body: <p>I use pip install packages in a conda environment.</p>
  <pre><code>pip install pygame
  Requirement already satisfied: pygame in ./anaconda3/lib/python3.6/site-packages (1.9.4)
  </code></pre>
  <p>where the current directory is <code>/Users/aptx4869</code>. However, when I type <code>conda list</code>, there is nothing in the current environment. What's wrong with it? Here's the directory where the environment is at</p>
  <pre><code>/Users/aptx4869/anaconda3/envs/rl
  </code></pre>
  <h2>Update</h2>
  <p>I delete the <code>pygame</code> in the root environment and run <code>pip install pygame</code> in the <code>rl</code> conda environment, I receive another message. But <code>pygame</code> still doesn't show in <code>conda list</code></p>
  <pre><code> pip install pygame
  Collecting pygame
    Using cached https://files.pythonhosted.org/packages/bc/19/57bf1e9c72be4f7afc1add56cc717b7f7fe8ef1b6b5fb58f031a06401d0f/pygame-1.9.4-cp36-cp36m-macosx_10_11_intel.whl
  Installing collected packages: pygame
  Successfully installed pygame-1.9.4
  (rl)
  </code></pre>
  <p>Notice <code>(rl)</code> in the end, this <code>pip</code> command still installs <code>pygame</code> in the root environment</p>