Python version compatibility

[Budsy]

I'm new to Python, though I know about 10 other languages. I have a general question about the nature of Python's version inter-operability. I once had the experience of downloading a Python app to try out on my system, on which I had just installed a most-recent version of Python. I was dismayed to find that the downloaded script would not work with my Python. It didn't crash, it just aborted. I supposed then that I would have to install an additional version of Python just for this one script. Instead, I wiped Python off my machine. Now, I'm giving Python another look, but am worried that I might be continually facing version conflicts. So, can experienced folks give me any advice on the issues surrounding downward compatibility and with compatibility involving libraries, plugins, etc? Shorter version of question: Is versioning conflicts with Python a common or uncommon issue to deal with?

[wavic]

I don't have to think about this. I am using Linux and I have both major versions of Python installed by default. All I have to do eventually is to install a module if needed.

When I write a script I use Python 3. Version 2 support stops in two years.

In general, you need the proper version to run the script. It's possible to convert it from 2 to 3 using 2to3 but honestly, I never used it so can't tell how it behaves. But here comes another ... thing. If the script needs a third party module this module have to be ported to the same version too.

Most of the modules out there are ported but still, there are some abandoned projects which need a little push.
Almost everyone prefers to code in Python 3 if there is a choice. The script you have downloaded must have been an old one.

[metulburr]

Its the same with every other language. As the language progresses there are version conflicts. Every major language has version conflicts. You cant run c++98 compiler on code that was expected to be compiled under c++11, python3.x code on a 2.x interpreter, java9 code on java6, etc.

[wavic]

Its the same with every other language. As the language progresses there are version conflicts. Every major language has version conflicts. You cant run c++98 compiler on code that was expected to be compiled under c++11, python3.x code on a 2.x interpreter, java9 code on java6, etc.

This is why I deleted all the old programming books I collected during the years.

[Budsy]

So if it's mostly an issue that arises with just the major two extant versions, I can see dealing with that. I asked because I really think some languages are more prone to conflicts than others. (PHP has presented more issues for me than most.) Well anyway, all your comments make me feel confident about re-installing Python.

[metulburr]

Its mostly been python 2.x and python 3.x. and yes soon everyone will be swayed to 3. However python 3.6 has added quite a bit that previous interpreter versions cannot run compared to the norm.

[DeaD_EyE]

• Python 2.7 is supported till 2020, after this date it may be supported by companies as paid service.
  
• Python 3 is in Arch Linux and some other distributions already standard
  
• Most important third party modules are supporting both Python version.
  
• The Numpy developers announced to remove the support for Python 2.7
  

It is better to use now Python 3, as waiting until 2020 and getting into much trouble.
You should have installed Python 2.7 and Python >=3.5. Many tools still support only Python 2.7.

The situation is now better than 2 years before. But we still have some Python 2.7 dependencies :-/

[metulburr]

after this date it may be supported by companies as paid service.

Link?

[DeaD_EyE]

There is no link. I am the source :-D

It's a speculation. That the support for Python 2.7 will stopped 2020 has been announced: https://pythonclock.org/
There is a possibility, that companies doing support for Python 2.7 after 2020, but it's not clear.

[metulburr]

Hmm, if that is true, then let it be known that support here will be given for free. I hate when companies take advantage. A lot of people will still be using 2.x after 2020 due to them not having control to update