Creating Virtual Environments (Windows + Linux)

🔎 Why Do We Need Virtual Environments?

1. Isolation of Dependencies for Different Projects

• Project A requires <span>numpy==1.21</span>

• Project B requires <span>numpy==1.26</span> If installed directly in the system environment, they will conflict; virtual environments allow them to exist independently.

Avoid Polluting the System Environment

• The system’s built-in Python (e.g., <span>/usr/bin/python3</span>) may depend on some critical libraries, and installing packages randomly may cause issues with system tools.

• Virtual environments only modify within the project directory/conda environment and will not affect the system.

Convenient for Deployment and Migration

• Dependencies of the virtual environment can be accurately recorded through <span>requirements.txt</span> or <span>environment.yml</span>, allowing for one-click reproduction on another machine.

• Suitable for team collaboration, ensuring everyone has the same running environment, avoiding “It works on my machine, but not on yours” issues.

Multiple Versions of Python Coexisting

• Sometimes a project requires Python 3.8, while another requires Python 3.11.

• Virtual environments allow you to manage multiple versions on a single machine.

Security

• When testing third-party libraries, they can be placed in a virtual environment to avoid irreversible effects on the system environment.

📌 When is it Necessary to Use a Virtual Environment?

• Developing multiple projects on the same machine, each with different dependency versions

• Conducting research/data science, requiring frequent trials of different versions of ML/DL libraries

• Wanting to avoid damaging the system’s built-in Python environment (especially on Linux/Mac)

• Team collaboration, ensuring everyone has a consistent environment

• Need to quickly deploy projects on new machines/servers

💻Creating, Activating, and Deleting Virtual Environments on Windows1. Anaconda is already installedanaconda

Create a new folder to place the virtual environment and the loaded packages:

2. Open this:

3. Preparation:

4. Create a virtual environment:

conda create -n mitsui python=3.11

5. Activate the virtual environment:

6. Use the virtual environment:

7. Check which virtual environments are on your computer:

conda env list

8.Delete a virtual environment:

For example: to delete the virtual environment namedmitsui this will completely remove the environment and all its installed packages.

conda remove -n mitsui --all

🖥️LinuxCreate a new virtual environment

1. Create a virtual environment (directory name myenv)

python3 -m venv myenv

2. Activate the virtual environment

source myenv/bin/activate

3. Deactivate the virtual environment

deactivate