Part 1

Code Layout

Line Structure


Python uses indentation levels to determine where the next line belongs to. I use Gedit with the Draw Spaces plugin enabled. In Gedit go to Edit > Preferences > Plugins and select the Draw Spaces Plugin.

Do not mix tabs and spaces in Python code. It is best to use spaces only for indentation. I personally use 2 spaces for indentation.

Indentation Example
if foo == 'time':
  print 'foo'
  print 'not foo'

class jt_gui:
  def __init__(self, inifile):
    self.foo2 = 'x'

  def foo3(self):
    self.foo3 = 'y'

Line Length

Limit line length to 79 characters. Two or more physical lines can be joined into a logical line with explicit line joining or implicit line joining.

A line ending in a backslash cannot carry a comment. A backslash does not continue a comment.

Explicit line joining
if 1900 < year < 2100 and 1 <= month <= 12 \
   and 1 <= day <= 31 and 0 <= hour < 24 \
   and 0 <= minute < 60 and 0 <= second < 60:   # Looks like a valid date
    return 1

Expressions in parentheses, square brackets or curly braces can be split over more than one physical line without using backslashes.

Implicit line joining
month_names = ['Januari', 'Februari', 'Maart',      # These are the
               'April',   'Mei',      'Juni',       # Dutch names
               'Juli',    'Augustus', 'September',  # for the months
               'Oktober', 'November', 'December']   # of the year