| # (C) Copyright David Abrahams 2002. Permission to copy, use, modify, sell and |
| # distribute this software is granted provided this copyright notice appears in |
| # all copies. This software is provided "as is" without express or implied |
| # warranty, and with no claim as to its suitability for any purpose. |
| |
| import operator |
| |
| def unique (values, stable=False): |
| if stable: |
| s = set() |
| r = [] |
| for v in values: |
| if not v in s: |
| r.append(v) |
| s.add(v) |
| return r |
| else: |
| return list(set(values)) |
| |
| def max_element (elements, ordered = None): |
| """ Returns the maximum number in 'elements'. Uses 'ordered' for comparisons, |
| or '<' is none is provided. |
| """ |
| if not ordered: ordered = operator.lt |
| |
| max = elements [0] |
| for e in elements [1:]: |
| if ordered (max, e): |
| max = e |
| |
| return max |
| |
| def select_highest_ranked (elements, ranks): |
| """ Returns all of 'elements' for which corresponding element in parallel |
| list 'rank' is equal to the maximum value in 'rank'. |
| """ |
| if not elements: |
| return [] |
| |
| max_rank = max_element (ranks) |
| |
| result = [] |
| while elements: |
| if ranks [0] == max_rank: |
| result.append (elements [0]) |
| |
| elements = elements [1:] |
| ranks = ranks [1:] |
| |
| return result |
