count the frequency that a value occurs in a dataframe column

Question

I have a dataset

|category|
cat a
cat b
cat a

I\'d like to be able to return something like (showing unique values and frequency)

Answer 1

your data:

|category|
cat a
cat b
cat a

solution:

 df['freq'] = df.groupby('category')['category'].transform('count')
 df =  df.drop_duplicates()