1 #

     2 # Copyright (c) 2008-2015 Thierry Florac <tflorac AT ulthar.net>

     3 # All Rights Reserved.

     4 #

     5 # This software is subject to the provisions of the Zope Public License,

     6 # Version 2.1 (ZPL).  A copy of the ZPL should accompany this distribution.

     7 # THIS SOFTWARE IS PROVIDED "AS IS" AND ANY AND ALL EXPRESS OR IMPLIED

     8 # WARRANTIES ARE DISCLAIMED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED

     9 # WARRANTIES OF TITLE, MERCHANTABILITY, AGAINST INFRINGEMENT, AND FITNESS

    10 # FOR A PARTICULAR PURPOSE.

    11 #

    12 

    13 __docformat__ = 'restructuredtext'

    14 

    15 

    16 # import standard library

    17 

    18 # import interfaces

    19 

    20 # import packages

    21 

    22 

    23 def unique(seq, idfun=None):

    24     """Extract unique values from list, preserving order

    25 

    26     >>> from pyams_utils.list import unique

    27     >>> mylist = [1, 2, 3, 2, 1]

    28     >>> unique(mylist)

    29     [1, 2, 3]

    30     """

    31     if idfun is None:

    32         def idfun(x): return x

    33     seen = {}

    34     result = []

    35     for item in seq:

    36         marker = idfun(item)

    37         if marker in seen:

    38             continue

    39         seen[marker] = 1

    40         result.append(item)

    41     return result