Moving from Python 2.6 to Python 3

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)

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