dictionary - Get the value of particular key from all dictionaries Python -

i have list of dictionary this,

a = [{'segmentname': 'fico high', 'cohortmonthyear': '01-01-2015', 'drivervalue': '0.921996823602789',       'monthsonbooks': '1',       'cohortquarteryear': 'q1 2015', 'portfolioid': '55dc0e48c95a8a1a2ffb836e', 'drivername': 'active rate'},      {'segmentname': 'fico high', 'cohortmonthyear': '01-01-2015', 'drivervalue': '0.9123400335106416',       'monthsonbooks': '2', 'cohortquarteryear': 'q1 2015', 'portfolioid': ('55dc0e48c95a8a1a2ffb836e'),       'drivername': 'active rate'},      {'segmentname': 'fico high', 'cohortmonthyear': '01-01-2015', 'drivervalue': '0.9024207736261439',       'monthsonbooks': '3', 'cohortquarteryear': 'q1 2015', 'portfolioid': ('55dc0e48c95a8a1a2ffb836e'),       'drivername': 'active rate'},      {'segmentname': 'fico high', 'cohortmonthyear': '01-01-2015', 'drivervalue': '0.889915542915732',       'monthsonbooks': '4',       'cohortquarteryear': 'q1 2015', 'portfolioid': ('55dc0e48c95a8a1a2ffb836e'), 'drivername': 'active rate'},      {'segmentname': 'fico high', 'cohortmonthyear': '01-01-2015', 'drivervalue': '0.8806580068608421',       'monthsonbooks': '5', 'cohortquarteryear': 'q1 2015', 'portfolioid': ('55dc0e48c95a8a1a2ffb836e'),       'drivername': 'active rate'},      {'segmentname': 'fico high', 'cohortmonthyear': '02-01-2015', 'drivervalue': '0.9458702933667549',       'monthsonbooks': '1', 'cohortquarteryear': 'q1 2015', 'portfolioid': ('55dc0e48c95a8a1a2ffb836e'),       'drivername': 'active rate'},      {'segmentname': 'fico high', 'cohortmonthyear': '02-01-2015', 'drivervalue': '0.9335318149106486',       'monthsonbooks': '2', 'cohortquarteryear': 'q1 2015', 'portfolioid': ('55dc0e48c95a8a1a2ffb836e'),       'drivername': 'active rate'},      {'segmentname': 'fico high', 'cohortmonthyear': '02-01-2015', 'drivervalue': '0.9225337221412799',       'monthsonbooks': '3', 'cohortquarteryear': 'q1 2015', 'portfolioid': ('55dc0e48c95a8a1a2ffb836e'),       'drivername': 'active rate'},      {'segmentname': 'fico high', 'cohortmonthyear': '02-01-2015', 'drivervalue': '0.9109689291572624',       'monthsonbooks': '4', 'cohortquarteryear': 'q1 2015', 'portfolioid': ('55dc0e48c95a8a1a2ffb836e'),       'drivername': 'active rate'},      {'segmentname': 'fico high', 'cohortmonthyear': '03-01-2015', 'drivervalue': '0.9092991755453589',       'monthsonbooks': '1', 'cohortquarteryear': 'q1 2015', 'portfolioid': ('55dc0e48c95a8a1a2ffb836e'),       'drivername': 'active rate'},      {'segmentname': 'fico high', 'cohortmonthyear': '03-01-2015', 'drivervalue': '0.8988101317456371',       'monthsonbooks': '2', 'cohortquarteryear': 'q1 2015', 'portfolioid': ('55dc0e48c95a8a1a2ffb836e'),       'drivername': 'active rate'},      {'segmentname': 'fico high', 'cohortmonthyear': '03-01-2015', 'drivervalue': '0.8860809446836048',       'monthsonbooks': '3', 'cohortquarteryear': 'q1 2015', 'portfolioid': ('55dc0e48c95a8a1a2ffb836e'),       'drivername': 'active rate'},      {'segmentname': 'fico high', 'cohortmonthyear': '04-01-2015', 'drivervalue': '0.9471495415096017',       'monthsonbooks': '1', 'cohortquarteryear': 'q2 2015', 'portfolioid': ('55dc0e48c95a8a1a2ffb836e'),       'drivername': 'active rate'},      {'segmentname': 'fico high', 'cohortmonthyear': '04-01-2015', 'drivervalue': '0.9364314248533585',       'monthsonbooks': '2', 'cohortquarteryear': 'q2 2015', 'portfolioid': ('55dc0e48c95a8a1a2ffb836e'),       'drivername': 'active rate'},      {'segmentname': 'fico high', 'cohortmonthyear': '05-01-2015', 'drivervalue': '0.9344317261744861',       'monthsonbooks': '1', 'cohortquarteryear': 'q2 2015', 'portfolioid': ('55dc0e48c95a8a1a2ffb836e'),       'drivername': 'active rate'}] 

i need iterate on list of dictionaries , drivervalue of dictionary without repeating segmentname , drivername , portfolioid.

this code far,

mm = [] in a:     ss = {'drivername': i['drivername'], 'segmentname': i['segmentname'], 'portfolioid': i['portfolioid'],           'drivervalue': []}      if all([i['drivername'] == 'drivername' , i['segmentname'] == 'segmentname']):         ss['drivervalue'].append(i['drivervalue'])      mm.append(ss)  print(mm) 

the drivervalue empty in list. doing wrong?

sample output:

{     "portfolioid" : ("55d4247b119a612af00eff4b"),     "drivername" : "active rate",     "sampledata" : [          30,          24,          6,          9,          9,          9,          9,          9,          9,          9,          9,          9,          9,          9,          9,          9,          9,          9,          9,          9,          9,          9,          9,          9     ] } 

theres more elegant approach this, key value pairs each occurrence of "drivervalue" key in list of dictionaries, , store values in list mm:

mm = [] b in a:     key,value in b.items():         if key == "drivervalue":             mm.append(value) 

just played around , approach is:

p = [d['drivervalue'] d in a] 

where p list of values. hope helps.