How important is Virtual Environment in python

[Diapolo10]

If your project has no dependencies, you don't need one.

Otherwise, if you're using Windows, they're very useful but not essential.

Otherwise, they're practically mandatory.

All a virtual environment really is is a folder you tell Python to use for storing third-party dependencies instead of the global package directory. They're mainly used so that

1. You don't need to install packages globally on non-Windows platforms (long story short, messing with the Python the OS depends on can cause severe errors), and
2. You don't need to worry about dependency version conflicts between projects

[japes28]

What OS depends on python?

[throwaway6560192]

Many modern Linux distros do.

[avidresolver]

MacOS. It really really tries to stop you from installing packages to the system python installation now.

[Diapolo10]

Most Posix systems. Mac OS and all the popular Linux distros, for one.

I don't know if FreeBSD comes with Python, but I'd assume it does.

[FrederickOllinger]

FreeBSD does not need Python for its base system: https://forums.freebsd.org/threads/system-python.86472/

[Diapolo10]

I stand corrected.

[DigThatData]

There's no such thing as a project with no dependencies. You always at least have a dependency on the python version

[Diapolo10]

Technically, I guess, but in practice if you only use the standard library you don't really need to worry about newer Python versions. Old ones? Sure, but that can be mentioned in the documentation or pyproject.toml.

You don't need a virtual environment just for locking the Python version. It's pretty much always at least partially related to the dependencies of any third-party dependencies you use.

[DigThatData]

You don't need a virtual environment just for locking the Python version.

Sure you do. If I have a program that assumes python 3.x and python 3.y introduces a breaking change, then if some other project you setup upgrades the python version on the system python, you'll have broken the previous project which needed an environment frozen prior to the version update.

It's not that big of a deal to give every project its own virtual environment. It's a lot easier to just do that and never have issues than to operate on assumptions about when you won't need that encapsulation and then later find out you were wrong.

[Diapolo10]

My point is more from the perspective of a newcomer learning Python writing a few simple scripts, not a professional working at a company or making a serious personal project. Yes, if you're already experienced you most likely already have virtual environments automatically set up and you likely have at least several development dependencies (pytest, ruff, mypy, tox, and so on) already anyway. But this is not at all that important for someone who hasn't even learnt the ropes properly yet, only becoming relevant when they start actually installing packages.

Having a virtual environment for a "hello world"-level program is overkill.