This directory contains documentation and tools that help with migrating code
from Python 2 to Python 3.

Before using any tools in this directory, you should apply 2to3 to all of your
Python code. Review the output of 2to3 carefully before you invoke it as
'2to3 -w' to actually write out its proposed changes to your Python files.
More info on 2to3 here: https://docs.python.org/3.6/library/2to3.html

Files in this directory:

* find_division_operators.py: A script that checks all Python files in a
  specified directory for division operators. This is helpful for identifying
  places where division operators may need to be changed to floor division
  operators to preserve the correct behavior under Python 3. Run the script
  without arguments to see how to use it. Complete documentation on the
  division operator change can be found here:
  https://www.python.org/dev/peps/pep-0238/

* py2to3checker.sh: A Bash script that checks files for possible Python 3
  compatibility issues. This will flag many--but not all--issues that Python's
  built-in "2to3" tool will not. Review the output of this script carefully
  as it flags many lines that may not be problematic (e.g. any line containing
  a division operator is flagged.) The script does not make any changes to
  files. You have to review the output, determine which lines in your code need
  to be changed, and make the appropriate changes yourself. Run the script
  without arguments to see how to use it.

* py3_remove_unnecessary_list_calls.sh: A script that changes some Python
  statements that test membership of an object in dictionary keys, values, or
  items, to be more efficient. You can run it with a single Python file as an
  argument; it will update the file and create a .bak copy of the original
  file. WARNING: In rare cases, this script may make breaking changes to your
  code. You should carefully review this script's changes to your Python files
  before you delete the corresponding .bak files. See the comments at the top
  of the script file for more information.

* py3_migration_guide.txt.rst: A guide to many of the incompatibilities between
  Python 2 and 3 that may be relevant to migrating your Python code.

* reindent.py: This script comes from the official Python 3 distribution. Use
  it to fix the indentation in your Python files. Mixing tabs and spaces in
  a Python source file will cause the file to be rejected by the Python 3
  interpreter, so you may have to run this script on some files to make them
  compatible with Python 3. Run this script with the '--help' command line
  option to see how to use it.