Virtual Environment For My First Python Program


Here We will create a virtual environment and code inside the environment.
So why virtual Environment?

  • to separate and isolate the packages we are using for different programs and projects.
  • working with code that depends on different versions of some library.
  • This issue happens a lot when dealing with Python 2 and Python 3.
  • Having different versions of packages installed can lead to a lot of confusion and bugs.

It’s much better to have separate environments for separate programs.

The module we use to create virtual environment here is called venv.

  • venv will install most recent version of python that is available.

To create a virtual environment, We have to decide upon a directory where we want to place it. And run venv module as script with directory path.

  • Suppose we want to create a virtual environment at home/dev:
    then change directory to the path as follows

     $cd home/dev

Now inside the directory we will run venv script:

     ~/dev$ python -m venv python-dev

What this does is:

  • creates python-dev directory if it doesn't exist
  • also creates directories inside it containing a copy of the python interpreter, the standard library and various supporting files.

Once we have created Virtual Environment, We have to activate it.

  • Run following command
    On Windows:


    Here, extension for activate file should be mentioned whether its .bat for cmd or .ps1 for Power shell.
    In cmd,


and in PowerShell,


Updated through comment
on Linux or Mac:

     source python-dev/bin/activate

After activating, we can start programming.
now create file.

  • if you have vs code installed then you can simply type code in your terminal.

     ~/dev/python-dev $ code

This opens a file in vscode editor.
Now we can code our first Python Program Here.

     def main():
         print("hello world!")
     if __name__=="__main__":
         print("file invoked")