how to create column with other dataframe as legend in python (groupby() alike)- pandas library-CodePudding

i want to use df2 as legend to my primary df ('main_df')

what "code" need to be ?

main_df = pd.DataFrame({'genre_NAME': ['comedy', 'action', 'horror'], 'genre_id': [nan, nan, nan]})

df2 = pd.DataFrame({'genre': ['comedy', 'horror'], 'id': [0, 1]})
 
#main_df is not relate to df2

some code
 
#result 

print(main_df)

*OUTPUT =* 'genre_NAME': ['comedy', 'action', 'horror'], 'genre_id': [0, nan,1]

CodePudding user response：

You can access and change a specific value in a dataframe with df.loc[]. So in your case:

for _, line in df2.iterrows():
    main_df.loc[main_df.genre_NAME == line.genre, "genre_id"] = line.id