Apply CSS class to Pandas DataFrame using to_html

Question

I'm having trouble applying the "classes" argument with the Pandas "to_html" method to style a DataFrame.

"classes: str or list or tuple, default None CSS class(es) to apply to the resulting Html table" from https://pandas.pydata.org/pandas-docs/stable/generated/pandas.DataFrame.to_html.html

I am able to render a styled DataFrame like this (for example):

df = pd.DataFrame([[1, 2], [1, 3], [4, 6]], columns=['A', 'B'])

myhtml = df.style.set_properties(**{'font-size': '11pt', 'font-family': 'Calibri','border-collapse': 'collapse','border': '1px solid black'}).render()

with open('myhtml.html','w') as f:

    f.write(myhtml)        

How can I style html output from a DataFrame using "classes" with "to_html" like this:

df.to_html('myhtml.html',classes=<something here>)

Answer 1

Pandas' to_html simply provides the output of a large string containing HTML table markup. The class argument is a convenience handler to give the <table> a class characteristic that will be referenced in a previously created CSS document that styles it. Hence, incorporate to_html into a wider HTML document build that references an external CSS.

Interestingly, to_html adds dual classes <table class="dataframe mystyle"> which can be referenced in CSS individually, .dataframe {...} .mystyle{...}, or together .dataframe.mystyle {...}.