将字典数据分组排序

一. 使用itertools.groupby() 函数对字典中的某一个字段分组

rows = [
{'address': '5412 N CLARK', 'date': '07/01/2012'},
{'address': '5148 N CLARK', 'date': '07/04/2012'},
{'address': '5800 E 58TH', 'date': '07/02/2012'},
{'address': '2122 N CLARK', 'date': '07/03/2012'},
{'address': '5645 N RAVENSWOOD', 'date': '07/02/2012'},
{'address': '1060 W ADDISON', 'date': '07/02/2012'},
{'address': '4801 N BROADWAY', 'date': '07/01/2012'},
{'address': '1039 W GRANVILLE', 'date': '07/04/2012'},
]

from operator import itemgetter
from itertools import groupby
# Sort by the desired field first
rows.sort(key=itemgetter('date'))
# Iterate in groups
for date, items in groupby(rows, key=itemgetter('date')):
    print(date)
    for i in items:
        print(' ', i)

输出结果如下

07/01/2012
 {'date': '07/01/2012', 'address': '5412 N CLARK'}
 {'date': '07/01/2012', 'address': '4801 N BROADWAY'}
07/02/2012
 {'date': '07/02/2012', 'address': '5800 E 58TH'}
 {'date': '07/02/2012', 'address': '5645 N RAVENSWOOD'}
 {'date': '07/02/2012', 'address': '1060 W ADDISON'}
07/03/2012
 {'date': '07/03/2012', 'address': '2122 N CLARK'}
07/04/2012
 {'date': '07/04/2012', 'address': '5148 N CLARK'}
 {'date': '07/04/2012', 'address': '1039 W GRANVILLE'}