How to merge pandas value_counts() to dataframe or use it to subset a dataframe

Question

I used pandas df.value_counts() to find the number of occurrences of particular brands. I want to merge those value counts with the respective brands in the initial dataframe.

Answer 1

Pandas DataFrame's merge and value_counts attributes are pretty fast, so I would combine the two.

df.merge(df['brand'].value_counts().to_frame(), how='left', left_on='brand',
         right_index=True, suffixes=('', 'x'))\
  .rename(columns={'brandx':'brand_count'})