When should you move your development to Python 3? When you're good and ready and you're certain that you'll not need to run your code on Python 2 again. Up to that point, the 2to3 utility will convert code for you.

Here's an example where I converted a short example script called "london" - using the -w option to write the file back, moving the old file to a .bak file. You can see in the reports the changes that have been made.

wizard:python graham$ 2to3 -w london
RefactoringTool: Skipping implicit fixer: buffer
RefactoringTool: Skipping implicit fixer: idioms
RefactoringTool: Skipping implicit fixer: set_literal
RefactoringTool: Skipping implicit fixer: ws_comma
--- london (original)
+++ london (refactored)
@@ -2,7 +2,7 @@
 
 vatrates = (15,17.5,20) ;
 
-paid = float(raw_input("Whatdya pay furit? "))
+paid = float(input("Whatdya pay furit? "))
 
 for vatrate in vatrates:
  factor = 100.0 / (100.0 + vatrate)
@@ -10,6 +10,6 @@
  shopkeeper = paid * factor
  osborne = paid - shopkeeper
 
- print "Vat rate",vatrate,", Storeman ",shopkeeper,", Chancellor ",osborne
+ print("Vat rate",vatrate,", Storeman ",shopkeeper,", Chancellor ",osborne)
 
- print "izedone"
+ print("izedone")
RefactoringTool: Files that were modified:
RefactoringTool: london
wizard:python graham$

See [unconverted] and [converted] code.


Picture - delegate on a Python Course earlier this week. (You learn a lot on our courses - and we make them fun! as well.
(written 2010-07-14)

 Y300 - Python 3 - What is new, what's changed and why
  [753] Python 3000 - the next generation - (2006-06-09)
  [1788] Python 2 to Python 3 / Python 3000 / Py3k - (2008-09-07)
  [1791] The road ahead - Python 3 - (2008-09-10)
  [2277] Python classes / courses - what version do we train on? - (2009-07-10)
  [2285] Great new diagrams for our notes ... Python releases - (2009-07-13)
  [2559] Moving the product forward - ours, and MySQL, Perl, PHP and Python too - (2010-01-01)
  [2778] Learning to program in Python 2 ... and / or in Python 3 - (2010-05-24)
  [4469] Sorting in Python 3 - and how it differs from Python 2 sorting - (2015-04-20)
  [4470] Testing in Python 3 - unittest, doctest and __name__ == __main__ too. - (2015-04-21)
  [4590] Progress on moving from Python 2 to Python 3 - training for both versions - (2015-12-01)
  [4649] Object and Static methods - what is the difference; example in Python 3 - (2016-02-17)
  [4650] Why populate object with values as you construct them? - (2016-02-18)
  [4711] Convering from Python 2 to Python 3 - an update, and the 2to3 utility - (2016-10-30)
  [4712] A reminder of the key issues to consider in moving from Python 2 to Python 3 - (2016-10-30)

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Previous and next or Horse's mouth home

Forward to Moved - Melksham Lorry Park

A long day in Melksham ...
Unpacking a Perl string into a list
Another toot of the trumpet
Moved - Melksham Lorry Park
Moving from Python 2.6 to Python 3
Old prices - what would the equivalent price have been in 1966?
Contact Information for Melksham Oak Community School
A move towards the family
Cycling in Melksham, and looking forward
Ruby - how does it compare and where is it the right language?