Python updating a dictionary based on most occurred item

I would maintain a dictionary of webpages and users like this:

d = {'login' : {'tom':1, 'jerry':0, 'dexter':2, 'deedee':3, 'buttercup':1},
     'ask' : {'tom':0, 'jerry':0, 'dexter':3, 'deedee':2, 'buttercup':1},
     'profile': {'tom':4, 'jerry':2, 'dexter':2, 'deedee':3, 'buttercup':1},
     'search': {'tom':1, 'jerry':0, 'dexter':2, 'deedee':0, 'buttercup':4},
}

where the key is the webpage and the value is a dictionary of users and webpage visits. Increment the count inside the dictionary of each page when a user visits. Then its simple to get the most frequent visitor to each page:

from collections import Counter

l = []
for key,dd in d.items():
    c = Counter(dd)
    l.append({key : c.most_common(1)[0]})
print(l)

Output:

[{'login': ('deedee', 3)}, {'ask': ('dexter', 3)}, {'profile': ('tom', 4)}, {'search': ('buttercup', 4)}]

Update:

To create your dictionary d you firstly need a list of pages and users:

pages = ['login', 'ask', 'profile', 'search']
users = ['tom', 'jerry', 'dexter', 'deedee', 'buttercup']

You can then create your dictionary using dictionary comprehension:

d = {page: {user: 0 for user in users} for page in pages}

There are two for loop here - one to iterate the pages and another the users for each page. You will then get a structure like this:

{'login': {'tom': 0, 'jerry': 0, 'dexter': 0, 'deedee': 0, 'buttercup': 0},
 'ask': {'tom': 0, 'jerry': 0, 'dexter': 0, 'deedee': 0, 'buttercup': 0},
 'profile': {'tom': 0, 'jerry': 0, 'dexter': 0, 'deedee': 0, 'buttercup': 0},
 'search': {'tom': 0, 'jerry': 0, 'dexter': 0, 'deedee': 0, 'buttercup': 0}}

After that it is quite simple to update the web page visit for each user:

d['login']['tom'] += 1