Modern Python Projects Transcripts
Chapter: Python versions and packages
Lecture: What are virtual environments?
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The problem with pip is that it installs all the packages in the same folder.
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So, how about we tell pip to temporary install packages in a different folder, and then we tell our Python interpreter to use that folder instead?
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Well, that's exactly what virtual environment does. A virtual environment is a special folder that contains a Python,
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binary and any additional packages that you install. When you activate a virtual environment,
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two things happen. First, you tell pip to install any new packages to that
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folder, and then you tell Python interpreter to use packages from that folder.
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Let's see an example. so, when we are not using a virtual environment and we tell pip to install Django 3,
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it's going to install it in the global site packages. And then, when we tell pip to install Django 2,
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is going to install the previous version of Django and install the new one,
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as we already saw. If we use the virtual environment, first we activate a specific folder that we want to use. Then we tell pip to install Django 3,
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and as you can see, it's going to be installed not in a global site Packages but in side this Django 3 application,
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and then we tell virtual environment to activate a different environment. And when we tell pip to install Django 2.2 this time,
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it's not going to uninstall anything because it's going to use site packages from a different folder
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then previously.