Demo/comparisons/sortingtest.py

   1 #! /usr/bin/env python
   2
   3 # 2)  Sorting Test
   4 #
   5 #     Sort an input file that consists of lines like this
   6 #
   7 #         var1=23 other=14 ditto=23 fred=2
   8 #
   9 #     such that each output line is sorted WRT to the number.  Order
  10 #     of output lines does not change.  Resolve collisions using the
  11 #     variable name.   e.g.
  12 #
  13 #         fred=2 other=14 ditto=23 var1=23
  14 #
  15 #     Lines may be up to several kilobytes in length and contain
  16 #     zillions of variables.
  17
  18 # This implementation:
  19 # - Reads stdin, writes stdout
  20 # - Uses any amount of whitespace to separate fields
  21 # - Allows signed numbers
  22 # - Treats illegally formatted fields as field=0
  23 # - Outputs the sorted fields with exactly one space between them
  24 # - Handles blank input lines correctly
  25
  26 import re
  27 import string
  28 import sys
  29
  30 def main():
  31     prog = re.compile('^(.*)=([-+]?[0-9]+)')
  32     def makekey(item, prog=prog):
  33         match = prog.match(item)
  34         if match:
  35             var, num = match.group(1, 2)
  36             return string.atoi(num), var
  37         else:
  38             # Bad input -- pretend it's a var with value 0
  39             return 0, item
  40     while 1:
  41         line = sys.stdin.readline()
  42         if not line:
  43             break
  44         items = line.split()
  45         items = map(makekey, items)
  46         items.sort()
  47         for num, var in items:
  48             print "%s=%s" % (var, num),
  49         print
  50
  51 main()