title: packages are already satisfied but can not import them
body: <p>I want to use pandas on jupyter-notebook. it is using python3.
  when I use </p>
  
  <pre><code>import pandas as pd
  </code></pre>
  
  <p>it says:</p>
  
  <blockquote>
    <p>ModuleNotFoundError: No module named 'pandas'</p>
  </blockquote>
  
  <p>but when I use:</p>
  
  <pre><code>pip install pandas
  </code></pre>
  
  <p>it returns:</p>
  
  <blockquote>
    <p>Requirement already satisfied: pandas in /usr/local/lib/python2.7/dist-packages (0.24.2)</p>
  </blockquote>
  
  <p>how can I import packages like this. it is set to use python3 but for pip command it see python2.7</p>