I understand to access the top left cell of a dataframe we need to use df.columns.name and I can see the pandas document on styling provides example to style row/column headers with apply_index (

Change the # within the function for font color or both.

To see the steps within the function check:

print(pd.DataFrame('', index=df.index, columns=df.columns))
print(df.iloc[0,0])

To assing a color to a specific index you can use

CodePudding user response：

You can use

Option 1. Cell is empty

Trick is to look at the output for print(df.style.set_table_styles().to_html()):

  <thead>
    <tr>
      <th  >&nbsp;</th>
      <th id="T_d7719_level0_col0"  >col1</th>
      ...
    </tr>
  </thead>

Notice: <th >&nbsp;</th>. We can access these class names and set the format. E.g. in this case, we access blank (level0 applying to all of level0, i.e. all cols and index too).

df.style.set_table_styles(
    [{'selector': '.blank',
      'props': [('background-color', 'IndianRed'),
                ('color', 'white')]
     }]
)

Result:

Option 2. Either df.columns.name or df.index.name, or both. One style to entire cell.

In either scenario, we will need .index_name instead of .blank. E.g.

df.columns.name = 'columns'

df.style.set_table_styles(
    [{'selector': '.index_name',
      'props': [('background-color', 'IndianRed'),
                ('color', 'white')]
     }]
)

Result:

Option 3. df.columns.name and df.index.name, different styles.

This one is a little more tricky, as we will need to add tr:nth-child(1) for columns.name and tr:nth-child(2) for index.name.

# just setting col and index name immediately inside `pd.DataFrame`
df = pd.DataFrame([[1,3],[2,4]], 
                  columns=pd.Index(['col1','col2'], name='columns'), 
                  index=pd.Index([0,1], name='index'))

df.style.set_table_styles(
    [{'selector': 'tr:nth-child(1) .index_name',
      'props': [('background-color', 'IndianRed'),
                ('color', 'white')]
     }, {'selector': 'tr:nth-child(2) .index_name',
      'props': [('background-color', '#EECACA'),
                ('color', 'black')]
     }]
)