Issue:

If I need to flatten a list of lists I use something like this list comprehension to flatten into a single list:

[item for sublist in l for item in sublist]

I have a dictionary where some of the values are list of lists and I need to flatten these into single lists prior to importing into Pandas.

Current data:

defaultdict(list,{'object network fake-1': [' host 10.0.0.1'],'object network fake12': [' host 10.0.0.12'],'object network fake2': [' host 10.0.0.2 '],'object network fake3': [' host 10.0.0.0 255.255.255.0'],'object network fake4': [' host 10.0.0.4'],'object network fake5': [' host 10.0.0.5'],'object-group network prt-apps': [' network-object object fake-1',' network-object object fake2',' network-object object fake3',' network-object object fake121'],'object-group network prt-apps2': [' network-object object fake4',' group-object prt-apps',[' network-object object fake-1',' network-object object fake2',' network-object object fake3',' network-object object fake121']],'object-group network prt-apps3': [' network-object object fake5',' group-object prt-apps2',[' network-object object fake4',' group-object prt-apps',[' network-object object fake-1',' network-object object fake2',' network-object object fake3',' network-object object fake121']]]})

Desired data structure:

defaultdict(list,{'object network fake-1': [' host 10.0.0.1'],'object network fake12': [' host 10.0.0.12'],'object network fake2': [' host 10.0.0.2 '],'object network fake3': [' host 10.0.0.0 255.255.255.0'],'object network fake4': [' host 10.0.0.4'],'object network fake5': [' host 10.0.0.5'],'object-group network prt-apps': [' network-object object fake-1',' network-object object fake2',' network-object object fake3',' network-object object fake121'],'object-group network prt-apps2': [' network-object object fake4',' group-object prt-apps',' network-object object fake-1',' network-object object fake2',' network-object object fake3',' network-object object fake121'],'object-group network prt-apps3': [' network-object object fake5',' group-object prt-apps2',' network-object object fake4',' group-object prt-apps',' network-object object fake-1',' network-object object fake2',' network-object object fake3',' network-object object fake121']})

I have searched SO for this and do not see an example that I could use. Is there a simple way to flatten these kind of 'list of list' containers within a dictionary value?

This is the way I have processed other dictionary structures when consuming in Pandas but it does not work with the first dictionary above:

pd.DataFrame(dict([ (k,pd.Series(v)) for k,v in asa.iteritems() ]))

The following does the job as I understand it (for your specific example this relies on the list + behaviour):

def unpack(l):j = []for i in l:if type(i) != list:j.append(i)else:j = j + unpack(i)return jj = {}
for k, v in l.items():j[k] = unpack(v)

Starting with the object as dict in your example:

l = {'object network fake-1': [' host 10.0.0.1'],'object network fake12': [' host 10.0.0.12'],'object network fake2': [' host 10.0.0.2 '],'object network fake3': [' host 10.0.0.0 255.255.255.0'],'object network fake4': [' host 10.0.0.4'],'object network fake5': [' host 10.0.0.5'],'object-group network prt-apps': [' network-object object fake-1',' network-object object fake2',' network-object object fake3',' network-object object fake121'],'object-group network prt-apps2': [' network-object object fake4',' group-object prt-apps',[' network-object object fake-1',' network-object object fake2',' network-object object fake3',' network-object object fake121']],'object-group network prt-apps3': [' network-object object fake5',' group-object prt-apps2',[' network-object object fake4',' group-object prt-apps',[' network-object object fake-1',' network-object object fake2',' network-object object fake3',' network-object object fake121']]]}

you end up with

j = {'object network fake12': [' host 10.0.0.12'],'object-group network prt-apps': [' network-object object fake-1',' network-object object fake2',' network-object object fake3',' network-object object fake121'],'object network fake-1': [' host 10.0.0.1'],'object network fake2': [' host 10.0.0.2 '],'object network fake3': [' host 10.0.0.0 255.255.255.0'],'object-group network prt-apps2': [' network-object object fake4',' group-object prt-apps',' network-object object fake-1',' network-object object fake2',' network-object object fake3',' network-object object fake121'],'object-group network prt-apps3': [' network-object object fake5',' group-object prt-apps2',' network-object object fake4',' group-object prt-apps',' network-object object fake-1',' network-object object fake2',' network-object object fake3',' network-object object fake121'],'object network fake4': [' host 10.0.0.4'],'object network fake5': [' host 10.0.0.5']}