Python: How to update value of key value pair in nested dictionary?

Question

i am trying to make an inversed document index, therefore i need to know from all unique words in a collection in which doc they occur and how often.

i have used this an

Answer 1

I agree you should avoid the extra classes, and especially __getitem__. (Small conceptual errors can make __getitem__ or __getattr__ quite painful to debug.)

Python dict seems quite strong enough for what you are doing.

What about straightforward dict.setdefault

    for keyword in uniques:                             #For every unique word do   
        for word in text:                               #for every word in doc:
            if (word == keyword):
                dictionary.setdefault(keyword, {})
                dictionary[keyword].setdefault(filename, 0)
                dictionary[keyword][filename] += 1

Of course this would be where dictionary is just a dict, and not something from collections or a custom class of your own.

Then again, isn't this just:

        for word in text:                               #for every word in doc:
            dictionary.setdefault(word, {})
            dictionary[word].setdefault(filename, 0)
            dictionary[word][filename] += 1

No reason to isolate unique instances, since the dict forces unique keys anyway.