Lightning talk at Python Bcn Meetup, Beginners session about differences between Python 2 vs. Python 3

1. {
Python 2 vs. Python 3
“event”: “Python BCN Meetup – Beginners session”
“author”: “Pablo Enfedaque”
“twi6er”: “@pablitoev56”

2. { “event”: “Python BCN Meetup”, “author”: “Pablo Enfedaque”, “twi6er”: “@pablitoev56”}
> December 1989: Guido Van Rossum starts
Python implementation
> January 1994: Version 1.0 released
> October 2000: Version 2.0 released
> December 2008: Version 3.0 released
> June 2009: Version 3.1 released
> July 2010: Version 2.7 released with backports
> 2014: current versions are 2.7.6 and 3.4
Python versions

3. { “event”: “Python BCN Meetup”, “author”: “Pablo Enfedaque”, “twi6er”: “@pablitoev56”}
> December 1989: Guido Van Rossum starts
Python implementation
> January 1994: Version 1.0 released
> October 2000: Version 2.0 released
> December 2008: Version 3.0 released
> June 2009: Version 3.1 released
> July 2010: Version 2.7 released with backports
> 2014: current versions are 2.7.6 and 3.4
WTF?!

4. { “event”: “Python BCN Meetup”, “author”: “Pablo Enfedaque”, “twi6er”: “@pablitoev56”}
Python 3 is
backwards incompatible

5. { “event”: “Python BCN Meetup”, “author”: “Pablo Enfedaque”, “twi6er”: “@pablitoev56”}
> Backwards incompatibilities
> print and exec become functions
> All classes are new-­‐‑style
> Massive usage of generators instead of lists
> All text (str) is Unicode and encoded text is
binary data (bytes)
> Other minor changes in std lib
Python 3.0

6. { “event”: “Python BCN Meetup”, “author”: “Pablo Enfedaque”, “twi6er”: “@pablitoev56”}
Why Python 3?

7. { “event”: “Python BCN Meetup”, “author”: “Pablo Enfedaque”, “twi6er”: “@pablitoev56”}
Mainly because of encodings
Why Python 3?

8. { “event”: “Python BCN Meetup”, “author”: “Pablo Enfedaque”, “twi6er”: “@pablitoev56”}
Google: Python encoding sucks

9. { “event”: “Python BCN Meetup”, “author”: “Pablo Enfedaque”, “twi6er”: “@pablitoev56”}
Google: Python 3 sucks

10. { “event”: “Python BCN Meetup”, “author”: “Pablo Enfedaque”, “twi6er”: “@pablitoev56”}
Really because of encodings??
Why Python 3?

11. { “event”: “Python BCN Meetup”, “author”: “Pablo Enfedaque”, “twi6er”: “@pablitoev56”}
Why should I move to Python 3?

12. { “event”: “Python BCN Meetup”, “author”: “Pablo Enfedaque”, “twi6er”: “@pablitoev56”}
> Proper encoding
> asyncio
> enums
> Standard library virtualenvs
> Exception chaining
> Single-­‐‑dispatch
> uni6est.mock
> contextlib
> “Be6er” GIL
> concurrent.futures
> selectors module
> Qualified names
> …
Python 3.4 new features (vs. 2.7)

13. { “event”: “Python BCN Meetup”, “author”: “Pablo Enfedaque”, “twi6er”: “@pablitoev56”}
Why people don’t use Python 3?

14. { “event”: “Python BCN Meetup”, “author”: “Pablo Enfedaque”, “twi6er”: “@pablitoev56”}
Why people don’t use Python 3?
No dependencies ported

15. { “event”: “Python BCN Meetup”, “author”: “Pablo Enfedaque”, “twi6er”: “@pablitoev56”}
Why people don’t use Python 3?
Laziness?

16. { “event”: “Python BCN Meetup”, “author”: “Pablo Enfedaque”, “twi6er”: “@pablitoev56”}
> Great features are waiting us in Python 3
> We are beyond half the planned life of Python 2.7
> Python 2.6 is officially retired with 2.6.9 release
> Most 3rd party dependencies already in Python 3
> Or we could return to OSS all that we have been given
> hZps://caniusepython3.com
> Porting to Python 3 is not such a big deal
> In most of the cases
> So, no more excuses
> It’s time to start moving to Python 3
Conclusions

17. { “event”: “Python BCN Meetup”, “author”: “Pablo Enfedaque”, “twi6er”: “@pablitoev56”}
Conclusions

18. { “event”: “Python BCN Meetup”, “author”: “Pablo Enfedaque”, “twi6er”: “@pablitoev56”}
Q&A
Thanks for coming!
Slides:
h6ps://speakerdeck.com/pablito56/
python-­‐‑2-­‐‑vs-­‐‑python-­‐‑3