title: Matplotlib is installed but not installed
body: <p>In the terminal, after I enter the python interpreter I use <code>help('modules')</code> to see which modules are installed but Numpy, matplotlib and scipy are not listed.</p>
  
  <p>When I try to import them, I get the following:</p>
  
  <blockquote>
    <p>ImportError: no module named xxx. </p>
  </blockquote>
  
  <p>However, when I try to install these modules using <code>apt-get install xxx</code> I get a message saying: </p>
  
  <blockquote>
    <p>python-xxx is already the newest version. </p>
  </blockquote>
  
  <p>Is it possible I somehow have two versions of python one with matplotlib, the other without it? Could this be linked to a separate problem I'm having with Spyder where the interpreter no longer works? See <a href="https://stackoverflow.com/questions/36072477/interpreter-stopped-working-in-spyder">here</a>.</p>
  
  <p>I am using python 2.7. When I run which python I get: <code>/usr/local/bin/python</code>.</p>
  
  <p>When I run <code>/usr/bin/local/python</code> I get:</p>
  
  <pre><code>Python 2.7.9 (default, Mar 18 2016, 20:34:01) 
  [GCC 4.8.4] on linux2
  </code></pre>
  
  <p>When I run <code>dpkg -l spyder</code> I get:</p>
  
  <pre><code>Desired=Unknown/Install/Remove/Purge/Hold
  | Status=Not/Inst/Conf-files/Unpacked/halF-conf/Half-inst/trig-   aWait/Trig-pend
  |/ Err?=(none)/Reinst-required (Status,Err: uppercase=bad)
  ||/ Name           Version      Architecture Description
  +++-==============-============-============-    =================================
  ii  spyder         2.3.0+dfsg-4 all          python IDE for scientists (Python
  </code></pre>