Virtual Environment for My First Python Program

Creating and using a virtual environment is a best practice when working on Python projects. It helps isolate dependencies and avoids conflicts between different projects.

Why Use a Virtual Environment?

• To isolate packages used in different projects.
• To avoid conflicts between library versions.
• Essential when working with both Python 2 and Python 3.
• Helps prevent bugs and confusion caused by global installations.
• Makes your projects portable and reproducible.

Module Used: venv

Python provides the venv module to create lightweight virtual environments. It includes a standalone Python interpreter and pip.

Example: Create a Virtual Environment in ~/dev

1. Navigate to your project directory

cd ~/dev

2. Create the virtual environment

python -m venv python-dev

This will:

• Create a folder python-dev (if it doesn’t exist)
• Copy the Python interpreter, standard library, and pip into it

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Activate the Virtual Environment

On Windows:

Command Prompt (CMD):

python-dev\Scripts\activate.bat

PowerShell:

python-dev\Scripts\Activate.ps1

On Linux / macOS:

source python-dev/bin/activate

Once activated, your terminal prompt will change to show the environment name:

(python-dev) $

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Writing Your First Python Program

1. Open VS Code in the environment directory:

cd python-dev
code main.py

2. Paste the following code in main.py:

def main():
    print("Hello, world!")

if __name__ == "__main__":
    main()
else:
    print("File invoked")

3. Run your script:

Make sure your virtual environment is activated, then run:

python main.py

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Deactivating the Environment

To deactivate the virtual environment when you're done:

deactivate