Question

I have a dictionary in python like this:

x = {country:{city:population}:……}

and I want to create a new dictionary like y = {country:cities_population}, where cities_population adds all the population in every city in every country and I really don’t know how to do it.

I tried this:

for country in x:
 for city, population in x[country].iteritems():
  if not country in y:
   y[country] = {}
  y[country] += population

I check for a dictionary with only one key and one value but I don’t understand how to manage a three items dictionary… help me please!!!! 🙂

Answer 1

Well, how about:

 y = {  }
 for country, cities in x.iteritems():
     y[country] = sum(cities.values())