Read on Twitter
The 2nd lesson I'd teach anyone learning Python 
will be about using Virtual Environments.
Surprisingly, I've found out that many developers learn about this well into their careers (like I did.)
Here is everything you need to know about Virtual Environments:
will be about using Virtual Environments.Surprisingly, I've found out that many developers learn about this well into their careers (like I did.)
Here is everything you need to know about Virtual Environments:
In short, Virtual Environments let you deal with dependencies. Basically, these are the libraries that your code needs to function.
(Who remembers "dll hell" back in the day when working with Microsoft products? If you don't, Google the term.)
(Who remembers "dll hell" back in the day when working with Microsoft products? If you don't, Google the term.)
Imagine that you are building your first Python project. You want to load the content of a URL from your code, so you install the "requests" library.
Easy peasy to do using "pip install requests"! See attached image: version 2.24.0 is installed.
Easy peasy to do using "pip install requests"! See attached image: version 2.24.0 is installed.
You finish your project, and all it's good and dandy!
But then, a month later, you decide to work on your second project. It also needs the "requests" library.
The latest version is not 2.24.0 anymore. Now version 3 is available! That's the one you want to use!
But then, a month later, you decide to work on your second project. It also needs the "requests" library.
The latest version is not 2.24.0 anymore. Now version 3 is available! That's the one you want to use!
So, what do you do?
You could upgrade your system to version 3, but then you'll be potentially breaking the first project you built that depends on 2.24.0!
Do you imagine this happening on a server with many more applications running?
You could upgrade your system to version 3, but then you'll be potentially breaking the first project you built that depends on 2.24.0!
Do you imagine this happening on a server with many more applications running?
Obviously, we need a way to deal with this, so enter virtual environments.
This first step for every new project is to create a virtual environment for it.
Some people have a central location where they store all of these. I prefer to store them in the project folder.
This first step for every new project is to create a virtual environment for it.
Some people have a central location where they store all of these. I prefer to store them in the project folder.
Using the built-in "venv" module in Python3 we can create a new virtual environment. In this case, I'm creating it inside the project folder.
Then, using "source" I can activate this environment.
At this point, we have full isolation for our project.
Then, using "source" I can activate this environment.
At this point, we have full isolation for our project.
Ar this point, if we install any libraries, they will be installed within the environment we are in, and will never mess with the libraries installed at the system level.
This is great!
(Make sure you add the .venv folder to .gitignore.)
This is great!
(Make sure you add the .venv folder to .gitignore.)
This covers the basics of why you want virtual environments in your life.
If you want to get further, take a look at @realpython's "Python Virtual Environments: A Primer" article.
https://realpython.com/python-virtual-environments-a-primer/
If you want to get further, take a look at @realpython's "Python Virtual Environments: A Primer" article.
https://realpython.com/python-virtual-environments-a-primer/
