python可分组字典

inushome

# -*- encoding: UTF-8 -*-
from collections import defaultdict
class News(object):
def __init__(self, title, type):
self.title =title
self.type = type
def __repr__(self):
return "{'title':'%s', 'type':%s}"%(self.title, self.type)

newses = [
News(u"宏观研究", 1),
News(u"策略报告", 1),
News(u"行业研究", 2),
News(u"公司研究", 3),
News(u"海外资讯", 3),
News(u"其他", 1)
]
#print newses
#{
#   1: [{'title':宏观研究, 'type':1}, {'title':策略报告, 'type':1}, {'title':其他, 'type':1}],
#   2: [{'title':行业研究, 'type':2}],
#   3: [{'title':公司研究, 'type':3}, {'title':海外资讯, 'type':3}]
#}
#方法一
d = {}
for n in newses:
if n.type not in d:
d[n.type] = []
d[n.type].append(n)
#print d
#方法二
d = {}
for n in newses:
d.setdefault(n.type, []).append(n)
#print d
#方法三
d = defaultdict(list)
for n in newses:
d[n.type].append(n)
#print d
#方法四
d = defaultdict(list)
map(lambda n:d[n.type].append(n),newses)
#print d
#方法五
d = defaultdict(list)
[d[n.type].append(n) for n in newses]
#print d
#输出
for key in d:
print key, d[key]
print '=============='
for key in d:
for value in d[key]:
print key, value
print '=============='