# 06-07-04
#v1.0.0
# caselesssort.py
# A sort function for lists of strings that is case insensitive.
# Copyright Michael Foord
# You are free to modify, use and relicense this code.
# No warranty express or implied for the accuracy, fitness to purpose or otherwise for this code....
# Use at your own risk !!!
# E-mail michael AT foord DOT me DOT uk
# Maintained at www.voidspace.org.uk/atlantibots/pythonutils.html
"""
The built in sort method for lists is case sensitive.
This means it can be unsuitable for sorting some lists of strings.
e.g. ['Apple', 'Pear', 'apple'].sort()
leaves 'Apple' and 'apple' at opposite ends of the list.
You can pass in a function to the sort method - but this can be very slow.
cSort still uses the sort method, so there isn't much performance hit, but it is caseless.
cSort can handle non-string members in the list without failing.
In addition cSort will sort any sets of entries for which entry1.lower() == entry2.lower()
i.e. cSort(['fish', 'FISH', 'fIsh'])
returns ['FISH', 'fIsh', 'fish']
You can turn this behaviour off by passing cSort an optional 'False' parameter.
i.e. cSort(['fish', 'FISH', 'fIsh'], False)
returns ['fish', 'FISH', 'fIsh']
"""
def cSort(inlist, minisort=True):
sortlist = []
newlist = []
sortdict = {}
for entry in inlist:
try:
lentry = entry.lower()
except AttributeError:
sortlist.append(lentry)
else:
try:
sortdict[lentry].append(entry)
except KeyError:
sortdict[lentry] = [entry]
sortlist.append(lentry)
sortlist.sort()
for entry in sortlist:
try:
thislist = sortdict[entry]
if minisort: thislist.sort()
newlist = newlist + thislist
except KeyError:
newlist.append(entry)
return newlist
if __name__ == '__main__':
list1 = ['pish', 'fish', 'FISH', 'Fish', 'PISH', 'FIsh', 'fiSH', 'Pish','piSH']
list2 = list(list1)
print 'Here is an unsorted list :'
print list1
list1.sort()
print 'Here is a list sorted using list.sort() :'
print list1
print 'Here is the list sorted using cSort(list) :'
print cSort(list2)
print 'Here is the list sorted using cSort(list, False) :'
print cSort(list2, False)
"""
TODO/ISSUES
CHANGELOG
06-07-04 Version 1.0.0
A working caseless sort.
Will be part of the caseless module, but also stands on it's own.
"""
