ENH: Enhance printing options for `Styler`: `head` and `tail` ?

[dennymarcels]

Is your feature request related to a problem?

More like an improvement.

Describe the solution you'd like

I just started playing around with pandas styling, and I noticed there is no way to print only the head and/or tail of a stylized DataFrame. It would be awesome if the styling could be applied to the whole df but then we could print only selected rows, like head and/or tail.

API breaking implications

I guess there could be a parameter passed to methods such as bar, or a new method to be appended to the end of a call.

Describe alternatives you've considered

I can apply the style to a slice of a DataFrame but then the styling function is applied to this slice only. What if I want to highlight_max to the whole df but print head/tail only?

[attack68]

Interesting idea.
After #41635, there are max_rows and max_cols mechanics which are expected to be added as keywords to: Styler.to_html(). Currently this is only equivalent to a head scenario. The parsing and rendering mechanics were quite complicated so the equivalent of a tail might be df[::-1].style.to_html(max_rows=100) for example.

Do comment on the PR or further if you have any good ideas.

I guess there could be a parameter passed to methods such as bar, or a new method to be appended to the end of a call.

Nope don't want to add kwargs where they are not relevant to the function, but more add kwargs to rendering methods, or add to styler.options namespace.

[dennymarcels]

To be more precise, I like it when I call the DataFrame as the last line of code in a Colab cell and only the first 5 and last 5 rows are rendered. I was thinking something along that idea.

It would be nice to be able to call df.stile.bar().head(), or df.stile.bar().tail(), or even df.stile.bar().headAndTail().

[attack68]

@dennymarcels please comment on #45176

[ivasve]

Hi @dennymarcels , did you have a look at issue #45176 if it has solved the issue you've been having?

[LinuxIsCool]

It's frustrating that max_rows can not be applied to a stylized dataframe.

[LinuxIsCool]

To deal with this for now, I just implemented this utility function in my code:

    def _truncate_dataframe(df, max_rows):
        return pd.concat([df.head(max_rows//2), df.tail(max_rows//2)])

[attack68]

The "stylized dataframe" discussed in this thread is actually a Styler class. Your utility function involves DataFrames and does not reference a Styler. For Styler have you considered the global pandas option styler.render.max_rows ? https://pandas.pydata.org/docs/user_guide/options.html#available-options

[LinuxIsCool]

Thanks @attack68 for the fast response. That did indeed help me, but there is still a nuance issue of the aesthetics of the truncation. I would like to see the head and tail of the dataframe rather than just the head as was pointed out by @dennymarcels in this thread.

Here is my example:

import pandas as pd
import panel as pn
pd.set_option('styler.render.max_rows', 5)

df = pd.DataFrame(list(range(20)))

# Define CSS style for the sapphire color on column 'A' header
styles = [
    {'selector': 'th.col_heading.level0.col0', 
     'props': [('background-color', 'blue'), ('color', 'white')]}
]

# Apply the style to the DataFrame
styled_df = df.style.set_table_styles(styles, overwrite=False)

styled_df

[attack68]

styled_df.hide(df.index[5:-5])