Introduction to Virtual Environments 1

What Is It?

A virtual environment is simply an isolated environment for Python projects.

Why Use Virtual Environments?

Provide isolation between system site directories.
Each project can have its own set of dependencies.

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Virtual Environments With Anaconda

anaconda

Creating A Virtual Environment

Docs

Let’s create a virtual environment called “aws”.
We will specify that this virtual environment should use Python version 3.7.

(base) rd$ conda create -n aws python=3.7
(base) rd$ 

Activating Virtual Environment

(base) rd$ conda activate aws 
(aws) rd$ 

Installing Packages

Installing packages from Anaconda

(aws) rd$ conda install boto3

Installing non-conda-packages

If a package is not available from conda or Anaconda.org, you may be able to find and install the package via conda-forge or with another package manager like pip.

(aws) rd$ pip install boto3

Create Requirements File

(aws) rd$ conda list -e > requirements.txt

Listing Virtual Environments

(aws) rd$ conda env list
# conda environments:
#
base                     /Users/rd/opt/anaconda3
aws                   *  /Users/rd/opt/anaconda3/envs/aws
(aws) rd$ 

Removing Virtual Environments

(aws) rd$ conda activate base 
(base) rd$ conda remove --name aws --all
Remove all packages in environment /Users/rd/opt/anaconda3/envs/aws:


## Package Plan ##

  environment location: /Users/rd/opt/anaconda3/envs/aws


The following packages will be REMOVED:

  ca-certificates-2020.1.1-0
  certifi-2019.11.28-py37_0
  ...

Proceed ([y]/n)? y

Preparing transaction: done
Verifying transaction: done
Executing transaction: done
(base) rd$ 

Create Virtual Environment

Using Requirements File

(aws) rd$ conda create --name=aws --file=requirements.txt

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Virtual Environments With Pipenv

pipenv docs

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Virtual Environments With venv

The One True Way

Create a VENV (Virtual ENVironment)

This is the One True Way…

python3 -m venv ./venv

venv module

Activate the venv

AND you have to activate the venv everytime you start working on the project in a shell.

cd _to your project_
source ./venv/bin/activate

# and you should see (venv) in your prompt...

venv module

Seeing what installed and freezing it.

To see what is in the venv

python3 -m pip freeze

# and then
python -m pip freeze > requirements.txt

And loading those dependencies for the venv

python -m pip -r requirements.txt

Wow. This way your repo doesn’t have all the code from all these packages.

And Make Sure

Make sure your .gitignore file has a line…

venv/

(Don’t put your venv up in your repo either!).

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The End

Parrot