title: What is the difference between pyenv, virtualenv, anaconda?
body: <p>I am a ruby programmer trying to learn python. I am pretty familiar with pyenv since it is like a copy and paste from rbenv. Pyenv helps allow to have more than one version of python in a system and also to isolate the python without touching sensitive parts of system.</p>
  <p>I suppose every python installation comes with pip package. What I still don't understand is, there are many good python libs out there that suggest to use this virtualenv and anaconda. I can even find a virtualenv plugin for pyenv.</p>
  <p>Now I am getting confused with the purpose of these two pyenv and virtualenv.
  worse inside pyenv there is a virtualenv plugin.</p>
  <p>My questions are:</p>
  <ul>
  <li>what is the difference between pyenv and virtualenv?</li>
  <li>Is there any difference in using  pip command inside both pyenv and virtualenv?</li>
  <li>what does this pyenv virutalenv do?</li>
  </ul>
  <p>Your explanation with example will be highly appreciated.</p>