Drawing solid line in pandas dataframe every time column value changes

I'd like to draw a solid line in my pandas dataframe everytime a value in column "product_basket" resets.

This is how my df looks like:

What I'd like it to be is:

Pls feel free to suggest also other ideas in order to achieve a similar result.

Thanks in advance,

Stefano

Solution

You can first get the indices where the product_basket isn't the same as the next one, and apply border-bottom CSS styling for the rows whose indices match them:

# `different` is a boolean series, we get the indices where it is True
different = df.product_basket.ne(df.product_basket.shift(-1))
inds = different[different].index

# for each row, `row.name` gives the index and if the condition is OK,
# we return a styling for the entire row with `len(row)`; else None
df.style.apply(lambda row: ["border-bottom: 2px solid blue;"]*len(row)
                           if row.name in inds
                           else [""]*len(row), axis=1)

With some sample data