Python Software Foundation survey finds that a significant number of Python developers are still using Python 2 for data analysis, computer graphics, and devops.
I think the biggest problem would be libraries which are not available in 3.x. I just rewrote a python script some time ago and the syntax changes were pretty easy to change with search and replace.
I don't see a problem. For one, it's been 15 years: the vast majority of libraries have been ported by now. And like you said, you can fix the syntax with basically a find/replace script, so any stragglers can be modified easily.
There really isn't any excuse to still be using Python 2 anymore
While I agree that people should have moved on for a while, the idea that porting Python 2 to 3 only involves "find and replace" or a tool like 2to3 is only true in the most trivial cases. Anything that touches bytes, unicode, network or files to do anything remotely involved needs a lot more care. I should know, our codebase still suffers from the occasional bug due to this, even though it's been years.
Not sure why it is a big deal for most things. I was a 2.7 die hard and was forced to move to 3.x a few years ago. Had to rewrite a bunch of crap at first but once it was done it's been a lot better than I thought it was going to be at first.
I get that. My job is mostly writing Python scripts to keep an old Fortran based framework going, so I cringe when people get married into a language like this. I feel that all code should be adaptable and be able to absorb upgrades and changes. But I certainly understand. From my perspective if they were to rework my old Fortran code, it would take them at least a year or more to do it well. Most companies don't want to spend that sort of effort.
Python's public API changes subtly, so minor changes in Python version can lead to massive changes in the version of dependencies you use.
A few years ago we developed a script to update Cassandra on Python 2.7.Y. Production environment used Python 2.7.X (it was 5 patch releases earlier).
This completely changed the cassandra library version. We had to go back 15 patch releases which annoying resulting in a breaking change in the Cassandra libraries API and wouldn't work on the dev environments Python.
Python 3 hasn't solved this, 2 years ago I was asked to look at a number of Machine Learning projects running in docker. Upgrading Python from 3.4 to 3.8 had a huge effect on dependencies and figuring out the right combination was a huge pain.
This is a solved problem in Java, Node.js has the same weakness but their changes to language spec are additive so old code runs on new releases (just not the inverse). Ruby has exactly the same issues as Python
I swear it's just as frustrating as Minecraft modding and picking the right forge version for all the mods you want. And OF COURSE your 2 favorite mods aren't on the same version so you can't use them together. I'm legit learning to mod Minecraft just so I can port them myself.
Both. There are many breaking changes that can make your code completely incompatible. Some people won't bother to port their code. Others could be using an obscure or niche library that hasn't been updated for 3 and can't port their code.
Third category, software provided as part of an ancient service contract that nobody is allowed to touch, even though the service partner stopped offering support for this particular software years ago. Ask me how I know
At the old job I was using IronPython (2.7) to write Grasshopper plug-ins in the Rhino CAD software. Luckily, it was mostly responsible for kicking off Python3 and Go subprocesses.
Now, the worst I’m stuck with is 3.8 for one of our repos using PyTorch.
At this point Python 2.7 should be forked into a new language. They could call it something like Daudin, after the person who coined the word Python for the genus of nonvenomous snakes
You'd have to find someone interested in maintaining it for at least security fixes and I'm guessing everyone capable is more interested in just working on new stuff for Python 3.