title: Python interpreters on OS X Yosemite - which one to use?
body: <p>I recently switched from Windows to Mac, and after installing PyCharm I had to specify an interpreter. In the drop down I could choose between 3 interpreters:</p>
  
  <ol>
  <li>Macintosh HD ▸ usr ▸ local ▸ Cellar ▸ python ▸ 2.7.9 ▸ Frameworks ▸ Python.framework ▸ Versions ▸ 2.7 ▸ bin</li>
  <li>Macintosh HD ▸ System ▸ Library ▸ Frameworks ▸ Python.framework ▸ Versions ▸ 2.7 ▸ bin</li>
  <li>Macintosh HD ▸ System ▸ Library ▸ Frameworks ▸ Python.framework ▸ Versions ▸ 2.6 ▸ bin</li>
  </ol>
  
  <p>(Actually I can se that there is also version 2.5 and 2.3 in that last folder, but these where not shown in PyCharm).</p>
  
  <p>However, if I type <code>python</code> in the Terminal and then type</p>
  
  <pre><code>import sys
  print sys.executable
  </code></pre>
  
  <p>i get:</p>
  
  <ol start="4">
  <li><code>/usr/local/opt/python/bin/python2.7</code></li>
  </ol>
  
  <p>To make it even more confusing, when I type the same thing in IPython Notebook (run from the Terminal using <code>ipython notebook</code>) I get:</p>
  
  <ol start="5">
  <li><code>/usr/bin/python</code></li>
  </ol>
  
  <p>Questions:</p>
  
  <ul>
  <li>If I want to use Python 2.7 (I have 3 to choose between), which one should I use?</li>
  <li>How do I navigate between these interpreters (if I want to <code>pip install</code> on different ones)?</li>
  </ul>