Python basics, dataframe iteration - calculating average number of ratings

Question

In dataframe I have columns such as prime_genre and user_rating. I want to calculate average number of ratings (to do that i try to summarize ratings for each app and then divide by number of apps occurrences). My solution looks like this:

total=0
len_genre=0
for genre in prime_genre:
    for i in iosfree['prime_genre']:
        if(i == genre):
            len_genre += 1
            total += iosfree.loc[iosfree['prime_genre']==i, 'user_rating']  
    print("Genre: ", genre, "Average rating: ", total/len_genre)

Result looks like this:

Genre:  Music Average rating:  0      NaN
5      NaN
43     NaN
48     NaN
51     NaN

Average rating shouldn't be zero. Could you please give me some advice how to fix it? I am new to Python.

https://stackoverflow.com/questions/20109391/how-to-make-good-reproducible-pandas-examples — coffeinjunky, Aug 08 '21 at 15:03

score 1 · Accepted Answer · answered Aug 08 '21 at 15:24

1

Sounds like you can do with groupby with agg

df.groupby('prime_genre')['user_rating'].agg(['count','mean'])

answered Aug 08 '21 at 15:24

BENY

317,841
20
164
234

exactly what i was looking for, thank you a lot! – Banana Aug 08 '21 at 15:32

Python basics, dataframe iteration - calculating average number of ratings

1 Answers1