A Hodgepodge of Python(blog.adku.com)

    $ python -mtimeit -s'l=range(1000)' 'l[::-1]'      
    100000 loops, best of 3: 3.05 usec per loop
    $ python -mtimeit -s'l=range(1000)' 'l.reverse()'  
    1000000 loops, best of 3: 0.535 usec per loop
    $ python -mtimeit -s'l=range(1000)' 'a=reversed(l)' 
    1000000 loops, best of 3: 0.39 usec per loop

  a = {}
  a['foo'] = a.get('foo',0) + 1
  # a = {'foo':1}
  a['foo'] = a.get('foo',0) + 1
  # a = {'foo':2}

  occurrences = defaultdict(int)
  digraphs = defaultdict(lambda: defaultdict(int))
  
  prev_ch = None
  for ch in long_text:
    occurrences[ch] += 1
    if prev_ch is not None:
      digraphs[prev_ch][ch] += 1
    prev_ch = ch

  print "Occurrences:"
  for ch, count in sorted(occurrences.iteritems()):
    print "  %s: %i" % (ch, count)

  print "Digraph occurences:"
  for ch1, counts in sorted(digraphs):
    for ch2, count in sorted(counts):
      print "  %s%s: %i" % (ch1, ch2, count)

  >>> 
  >>> class PrefixStr:
  ...   def __init__(self, prefix):
  ...     self.prefix = prefix
  ...   def __getattr__(self, s):
  ...     return self.prefix+s
  ... 
  >>> 
  >>> q = PrefixStr('xyz_')
  >>> 
  >>> { q.height:11, q.width:7, q.depth:3 }
  {'xyz_width': 7, 'xyz_depth': 3, 'xyz_height': 11}
  >>>