### Here is my implementation to partition based on funct's evaluation.
def partition(iterable, func):
result = {}
for i in iterable:
result.setdefault(func(i), []).append(i)
return result
### Ian Bicking's Generalized group function
def group(seq):
'''seq is a sequence of tuple containing (item_to_be_categorized, category)'''
result = {}
for item, category in seq:
result.setdefault(category, []).append(item)
return result
########### Usage Example ###############
def is_odd(n):
return (n%2) == 1
l = range(10)
print partition(l, is_odd)
print group( (item, is_odd(item)) for item in l)
print group( (item, item%3) for item in l ) # no need for lamda/def
class Article (object):
def __init__(self, title, summary, author):
self.title = title
self.summary = summary
self.author = author
articles = [ Article('Politics & Me', 'about politics', 'Dave'),
Article('Fishes & Me', 'about fishes', 'ray'),
Article('Love & Me', 'about love', 'dave'),
Article('Spams & Me', 'about spams', 'Ray'), ]
# summaries of articles indexed by author
print group( (article.summary, article.author.lower()) for article in articles )
########### Output ###############
{False: [0, 2, 4, 6, 8], True: [1, 3, 5, 7, 9]}
{False: [0, 2, 4, 6, 8], True: [1, 3, 5, 7, 9]}
{0: [0, 3, 6, 9], 1: [1, 4, 7], 2: [2, 5, 8]}
{'dave': ['about politics', 'about love'], 'ray': ['about fishes', 'about spams']}
