Python
Virtual Environment
- Python
virtual environments
create a virtual installation
of Python
inside a
project directory.
- Benefit of
a virtual environment:
- Users can
install and
different
Python packages
for each
virtual environment
(and for the project)
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This allows users to
install
packages and
modify
their Python environment
without fear
of breaking packages
installed in
other environments.
- What can
a virtual environment
contain:
- A specific
Python interpreter and
software libraries
needed to
support a
project.
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These
project-specific
software are
stored in
a directory,
conventionally named
venv or
.venv
inside the
project directory.
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Creating and Activating a
Virtual Environment
in Python using
venv
- Command
to create a
new
virtual environment:
mkdir myProj // Make directory for project "myProj"
cd myProj
python -m venv myvenv // Create virtual env "myvenv"
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- The utilities
for activating and
deactivating the
virtual environment
--- as well as the local copy
of Python interpreter
are placed in the
bin folder
(in Linux):
ls myvenv/bin
Activate.ps1 activate.csh pip* pip3.9* python3@
activate activate.fish pip3* python@ python3.9@
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- To activate the
virtual environment, run:
source myvenv/bin/activate
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Checking If Python is Running Inside a
Virtual Environment
- Start the
Python
interpreter:
- Import the
sys
module and
print the
sys.path
variable:
>>> import sys
>>> sys.path
You will see this path in the output:
'/home/cheung/python/02-env/myProj/myvenv/lib/python3.9/site-packages'
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