[PLUG] Python Guru Here?

[Rich Shepard]

On Tue, 12 Jul 2005, Russell Senior wrote:

> This is where an example of what you are putting-in/getting-out would be
> most helpful. There are a thousand ways you could be screwing up, please
> don't make us guess which.

   I didn't think it appropriate for the full list, and thought that
plug-programming was dead. Anywho, this is the current error message:

[rshepard at salmo ~/data/fuzzyEI-assessor/code]$ ./scoping-pairs.py 10 2
Traceback (most recent call last):
   File "./scoping-pairs.py", line 61, in ?
     combos(m, n)
NameError: name 'm' is not defined

   The source file is attached. I know it's a simple error of the head
slapping kind.

Rich

-- 
Dr. Richard B. Shepard, President      | 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
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#!/usr/bin/python
"""
  Takes a list of candidate environmental components and creates an
  output file of all combinations of components. Assumes input list
  name of 'components.in' and produces 'components.out'.
"""
import sys

def factorial(n):
  if n == 0:
    return 1
  else:
    return n * factorial(n-1)

def klistcombs(s, k):
    """Returns list of combinations of S taken K at a time.

    S must be a list.
    K must be >= 0.
    If K > len(S), an empty list is returned.
    Else if K is 0, a singleton list containing an empty list
    is returned.
    The k-combinations are returned in lexicographic order
    of their indices.
"""
    if k < 0:
        raise ValueError, "arg k == %d not >= 0" % k
    if len(s) < k:
        return []
    if k == 0:
        return [[]]

    answer = []
    indices = range(k)
    indices[-1] = indices[-1] - 1
    while 1:
        limit = len(s) - 1
        i = k - 1
        while i >= 0 and indices[i] == limit:
            i = i - 1
            limit = limit - 1
        if i < 0:
            break
        val = indices[i]
        for i in xrange( i, k ):
            val = val + 1
            indices[i] = val
        temp = []
        for i in indices:
            temp.append( s[i] )
        answer.append( temp )
    return answer        

def combos(m, n):
  num = factorial(m)
  denom = factorial(n) * factorial(m-n)
  c = num / denom
  return c
  
if __name__ == '__main__':
  combos(m, n)
  print num, denom, c