Group dict values into chunks with python

Question

I'm trying to figure out a way to group dictionary values into intervals, depending on the value of a key.

In my case, I have two keys: 'timestamp' and 'value'; I need to group it by intervals based on the value. My data structure is this one:

[{'timestamp': u'1389631816', 'value': u'0'},
 {'timestamp': u'1389633136', 'value': u'0'},
 {'timestamp': u'1389633256', 'value': u'1'},
 {'timestamp': u'1389633316', 'value': u'1'},
 {'timestamp': u'1389633196', 'value': u'0'},
 {'timestamp': u'1389633196', 'value': u'0'},
 {'timestamp': u'1389633196', 'value': u'0'},
 {'timestamp': u'1389633316', 'value': u'1'}]

In this case, I should have 4 groups:

First Group: 2 items, based on value '0';
Second Group: 2 items, based on value '1';
Third Group: 3 items, based on value '0';
Fourth Group: 1 item, based on value '1'.

For all purposes, I need metrics between times of these groups (Coming for ICMP checks from the Zabbix in this example) to create a report, but I'm really stuck here.

Answer 1

Use the itertools.groupby() function to group these:

from itertools import groupby
from operator import itemgetter

for value, group in groupby(list_of_dicts, key=itemgetter('value')):
    print 'Group for value {}'.format(value)
    for d in group:
        print d

Demo:

>>> from itertools import groupby
>>> from operator import itemgetter
>>> list_of_dicts = [{'timestamp': u'1389631816', 'value': u'0'},
...  {'timestamp': u'1389633136', 'value': u'0'},
...  {'timestamp': u'1389633256', 'value': u'1'},
...  {'timestamp': u'1389633316', 'value': u'1'},
...  {'timestamp': u'1389633196', 'value': u'0'},
...  {'timestamp': u'1389633196', 'value': u'0'},
...  {'timestamp': u'1389633196', 'value': u'0'},
...  {'timestamp': u'1389633316', 'value': u'1'}]
>>> for value, group in groupby(list_of_dicts, key=itemgetter('value')):
...     print 'Group for value {}'.format(value)
...     for d in group:
...         print d
... 
Group for value 0
{'timestamp': u'1389631816', 'value': u'0'}
{'timestamp': u'1389633136', 'value': u'0'}
Group for value 1
{'timestamp': u'1389633256', 'value': u'1'}
{'timestamp': u'1389633316', 'value': u'1'}
Group for value 0
{'timestamp': u'1389633196', 'value': u'0'}
{'timestamp': u'1389633196', 'value': u'0'}
{'timestamp': u'1389633196', 'value': u'0'}
Group for value 1
{'timestamp': u'1389633316', 'value': u'1'}