dictionary - Intersections between values in two dictionaries in python -

i have csv file contains trade data countries. data has format follows:

rep   par  commodity  value usa   ger    1         700 usa   ger    2         100 usa   ger    3         400 usa   ger    5         100 usa   ger    80        900 ger   usa    2         300 ger   usa    4         500 ger   usa    5         700 ger   usa    97        450 ger   uk     50        300 uk    usa    4         1100 uk    usa    80        200 uk    ger    50        200 uk    ger    39        650 

i intend make new dictionary , using created dictionary, calculate total value of common traded commodities between countries. example, consider trade between usa-ger, intend check whether ger-usa in data , if exists, values common commodities summed , same countries. dictionary should like:

dic_c1c2_producs= {('usa','ger'): ('1','700'),('2','100'),('3','400'),('5','100'),('80','900');  ('ger','usa'):('2','300'),('4','500'),('5','700'),('97','450') ; ('ger','uk'):('50','300');  ('uk','usa'): ('4','80'),('80','200');  ('uk','ger'): ('50','200'),('39','650')} 

as can see, usa-ger , ger-usa have commodities 2 , 5 in common , value of these goods (100+300)+(100+700). pairs usa-uk , uk-usa, have common commodities: 0 total trade 0 well. ger-uk , uk-ger, commodity 50 in common , total trade 300+200. @ end, want have like:

dic_c1c2_summation={('usa','ger'):1200;('ger','uk'):500; ('uk','usa'):0} 

any appreciated.

in addition post, have written following lines:

from collections import defaultdict rfile = csv.reader(open("filepath",'r')) rfile.next() dic_c1c2_products = defaultdict(set)  dic_c_products = {} country = set() row in rfile :       c1 = row[0]       c2 = row[1]       p = row[2]       country.add(c1) in country :     dic_c_products[i] = set() rfile = csv.reader(open("filepath")) rfile.next() in rfile:     c1 = i[0]     c2 = i[1]     p = i[2]     v=i[3]     dic_c_products[c1].add((p,v))     if not dic_c1c2_products.has_key((c1,c2)) :         dic_c1c2_products[(c1,c2)] = set()         dic_c1c2_products[(c1,c2)].add((p,v))      else:             dic_c1c2_products[(c1,c2)].add((p,v)) c_list = dic_c_products.keys() dic_c1c2_productsummation = set() in dic_c1c2_products.keys():     if dic_c1c2_products.has_key((i[1],i[0])):        p1, v1 in dic_c1c2_products[(i[0],i[1])]:            p2, v2 in dic_c1c2_products[(i[1],i[0])]:                if p1==p2:                   summation=v1+v2                   if not in dic_c1c2_productsum.keys():                        dic_c1c2_productsum[(i[0],i[1])]=(p1, summation)                   else:                        dic_c1c2_productsum[(i[0],i[1])].add((p1, summation))     else:           dic_c1c2_productsn[i] = " " 

# save data in file called data import pandas pd data = pd.read_csv('data', delim_whitespace=true) data['par_rep'] = data.apply(lambda x: '_'.join(sorted([x['par'], x['rep']])), axis=1) result = data.groupby(('par_rep', 'commodity')).filter(lambda x: len(x) >= 2).groupby(('par_rep'))['value'].sum().to_dict() 

at end result {'ger_uk': 500, 'ger_usa': 1200}