Pollution level using dictionaries

[klara]

Dear wavic, thank you for taking that much time and having so much patience with me.

I'll admit that the task looks much more intimidating than it really is at the end.

I don't like being handed solutions either because that doesn't add anything to my knowledge and at the end it is me who has to pass the exams.

And with this extended explanation you gave I understand things a lot better. So thank you so much, again! I found some new motivation for programming :)

So, after all the help you gave me, I want to share my final program with you, which is just slightly different from your last suggestion.

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def number_of_polluted_days(januar):
    k = {}
    for day, data in januar.items():
        for city, pollution in data.items():
            if city not in k:
                k[city]=0
            if pollution >=50:
                k[city] += 1
    return k

def average(januar):
    k = {}
    for day, data in januar.items():
        for city, pollution in data.items():
            if city in k:
                k[city].append(pollution)
            else:
                k[city]=[]
                k[city].append(pollution)
    for city in k:
        k[city] = sum(k[city])/len(k[city])
    return k