How to install modules into virtual environment which are already installed in global environment
<p>I tried to install matplotlib into my virtual environment, but it doesn't install, as messages below. It seems to say that it is already under the global /user/lib64 directory. How can I install it to my virtual enviroment? If I don't install it, I can not import it in my virtual enviroment.</p>

<pre><code>(my_env) [abigail@localhost environments]$ sudo pip install matplotlib
Requirement already satisfied: matplotlib in /usr/lib64/python3.5/site-packages
Requirement already satisfied: pytz in /usr/lib/python3.5/site-packages (from matplotlib)
Requirement already satisfied: cycler in /usr/lib/python3.5/site-packages (from matplotlib)
Requirement already satisfied: python-dateutil in /usr/lib/python3.5/site-packages (from matplotlib)
Requirement already satisfied: numpy&gt;=1.6 in /usr/lib64/python3.5/site-packages (from matplotlib)
Requirement already satisfied: pyparsing!=2.0.0,!=2.0.4,!=2.1.2,&gt;=1.5.6 in /usr/lib/python3.5/site-packages (from matplotlib)
Requirement already satisfied: six in /usr/lib/python3.5/site-packages (from cycler-&gt;matplotlib)
</code></pre>