Multiway Branching

[rshepard at salmo.appl-ecosys.com]

  I need to look at two-byte pairs coming from a machine, and interpret the
meaning based on the relative values of the two bytes. In C I'd use a switch
statement. Python doesn't have such a branching statement. I have 21
comparisons to make, and that many if/elif/else statements is clunky and
inefficient. Since these data are coming from an OMR scanner at 9600 bps (or
faster if I can reset it programmatically to 38K over the serial cable), I
want a fast algorithm.

  The data are of the form:

  if byte1 == 32 and byte2 == 32:
	row_value = 0
  elif byte1 == 36 and byte2 == 32:
	row_value = "natural"
   ...
  elif byte1 == 32 and byte2 == 1:
	row_value = 5
  elif byte1 == 66 and byte2 == 32:
	row_value = 0.167

  There are two rows where the marked response equates to a string and 28
rows where the marked response equates to an integer (1-9) or float of
defined values.

  Suggestions appreciated.

Rich 

-- 
Richard B. Shepard, Ph.D.               |   Author of "Quantifying Environmental
Applied Ecosystem Services, Inc. (TM)   |  Impact Assessments Using Fuzzy Logic"
<http://www.appl-ecosys.com>     Voice: 503-667-4517         Fax: 503-667-8863