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Should I learn python 2.x or start learning python 3
I'm just starting to learn Python, but just to use my time more efficiently, would you recommend to read Python2 or start directly from Python3? I'm about "Dive into Python". Is it similar to start reading PHP4 or PHP5? I'm trying to understand whether it's worth spending time on Python2 literature.
If you plan to use Python for real production work, IMHO Python 2.6/2.7 is still the way to go, since most major libraries haven't ported to v3 yet.
However, if you just want to learn Python for the sake of expanding your horizons and understanding what the language is about, by all means go with version 3.
P.S: I realize this question is a duplicate of at least 2-3 other questions. But it's one of those questions that has to be asked every few months, since these things are in constant flux, and the "current opinion" matters.
As Python (2.6.4) is still widely used, i would recommend starting with it. If you understand Python2, it will be easy for you to learn Python3...
You should always use what the community uses, which is Python 2.5-6 imho. Most of the 3th party libraries don't support 3.x yet so there is not a real big reason to switch onto Python3k for now.
Learn Python 3. Speaking from experience, it's not so hard to use 2 if you learned 3. If more people are impatient to use 3rd party libraries with 3, then perhaps some of them will contribute to the porting effort and we can all move to 3 sooner.
I'm going to strongly suggest going with Python 3. The issue is that you sound like a new young programmer and as such will be at it awhile. As such you might as well start learning the version that will be the standard for the next few years going forward.
As others have noted there are issues with some third party libraries but that is quickly changing. Frankly I'm going to flat out say you should avoid many of these libraries anyway until you get a good portion of Python under your belt. Also you might want to lok for better or more varied Python texts, hopefully something leveraging well the new features in Python 3.
Realize that, as already been pointed out, the differences are not huge. I'm just of the opinion that you should educate yourself for the future not the past. Especially if you develop code for yourself or customers.
Dave
Python 3 is a great place to start for those "with no baggage" (meaning no existing Python code or apps, no libraries/dependencies that haven't been ported to Python 3 yet, etc.).
However on the other hand, although Python 3 is here, most of the industrial world still runs on Python 2, so if you do need to create an app to run today using the libraries and packages available to you, that's where you should start. If you do, use any release 2.6 or newer as they have features backported from 3.x to help you start thinking in a 3.x kind of way. :-) If you learn one, it's easy to adapt to the other (and vice versa).
On a related note, I had the publishers add two new appendices (C & D) to the latest printing (5th!!) of my book, Core Python Programming, one on Python 3.x and the other on the importance of 2.6 and the role it plays in helping users to transition to Python 3.
Finally, I've been giving talks on Python 3 and covering the main differences from Python 2. Here's one that I gave a PyCon a few months ago which includes the slide preso.