2 # The Alphanum Algorithm is an improved sorting algorithm for strings
3 # containing numbers. Instead of sorting numbers in ASCII order like
4 # a standard sort, this algorithm sorts numbers in numeric order.
6 # The Alphanum Algorithm is discussed at http://www.DaveKoelle.com
8 #* Python implementation provided by Chris Hulan (chris.hulan@gmail.com)
9 #* Distributed under same license as original
11 # This library is free software; you can redistribute it and/or
12 # modify it under the terms of the GNU Lesser General Public
13 # License as published by the Free Software Foundation; either
14 # version 2.1 of the License, or any later version.
16 # This library is distributed in the hope that it will be useful,
17 # but WITHOUT ANY WARRANTY; without even the implied warranty of
18 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
19 # Lesser General Public License for more details.
21 # You should have received a copy of the GNU Lesser General Public
22 # License along with this library; if not, write to the Free Software
23 # Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
30 # TODO: Make decimal points be considered in the same class as digits
35 return a list of numbers and non-numeric substrings of +str+
36 the numeric substrings are converted to integer, non-numeric are left as is
38 if type(str) in types.StringTypes:
39 chunks = re.findall("(\d+|\D+)",str)
40 #convert numeric strings to numbers
41 chunks = [re.match('\d',x) and int(x) or x for x in chunks]
43 elif type(str) in [types.IntType, types.LongType, types.FloatType]:
46 raise ValueError("Unsupported type %s for input %s" % (type(str), str))
50 breaks +a+ and +b+ into pieces and returns left-to-right comparison of the pieces
52 +a+ and +b+ are expected to be strings (for example file names) with numbers and non-numeric characters
53 Split the values into list of numbers and non numeric sub-strings and so comparison of numbers gives
54 Numeric sorting, comparison of non-numeric gives Lexicographic order
56 # split strings into chunks
60 return cmp(aChunks,bChunks) #built in comparison works once data is prepared