In the earlier two posts of this series, I discussed about
conda and their usage along with some examples. I this post I am going to introduce you guys with another package and environment manager called
venv which comes with standard Python3.X by default. So, nothing to worry about its installation.
Creating an Environment
For example, If you have Python3.X installed in your system and you can run it’s REPL by issuing
python3 in the terminal, then you can create a virtual environment based on this Python version by issuing the following command:
python3 -m venv myvenv
This will create the
myvenv directory if it doesn’t exist, and also create directories inside it containing a copy of the Python interpreter, the standard library, and various supporting files. By the way, you got the idea of using different versions of Python to use its
venv module for creating different environments, right? Just find out an exact Python 3.X (I showed how, in earlier posts) and use its binary/executable in the command
<active python> -m venv <environment name> .
Activating the Environment
Its similar to the previous two workarounds and again simple as below. I assumed you are inside the newly created
Managing Packages with pip
venv is native with Python, you can use
pip for installing packages in your virtual environment which will pull down packages from Python’s official package repository, PyPI. For example, to install our very favorite package
numpy , use the following command,
pip install numpy
Also, for sure you can use commands like
pip search <packagename> ,
pip list in each newly created virtual environment.
Did you know, you can use
pip show <packagename>to see detail of an installed package in an active environment?
In the earlier post, I have discussed why and how you can share your environment made using
conda with others. If you are using
virtualenv then you can export an environment’s state/configuration to a file, issuing the following command,
pip freeze > requirements.txt
Here, the file name
requirements.txt , that contains environment’s package information could be anything. But people have been using this name conventionally for a long time.
So, after exporting the environment information, you can share this file to any one who can install exact same packages in his newly created virtual environment by using the following command:
pip install -r requirements.txt
By the way, sharing environment in this way is similar if you use