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

If your DataFrame has values with the same type, you can also set return_counts=True in numpy.unique().

index, counts = np.unique(df.values,return_counts=True)

np.bincount() could be faster if your values are integers.