Styling the background color of pandas index cell

Question

I want to change the background styling color of the pandas table. Example:

df = pd.DataFrame({
'group': ['A','B','C','D'],
'var1': [38, 1.5, 30, 4],
'var2': [29, 10, 9, 34],
'var3': [8, 39, 23, 24],
'var4': [7, 31, 33, 14],
'var5': [28, 15, 32, 14]
})

df.set_index('group', inplace=True)

I want the background color of the index cell (and just the index cell) A,C in blue and B,D in red.

I looked at the styling documentation but I could not find an example that matches this case.

user_9840637 · Answer

Based on the limitations of df.style, coloring index and columns is not implemented.

If you are okay to color the values based on the index, you can do something like this. Create a dictionary and apply the color based on the index using index.map

c1 = 'background-color: blue'
c2 = 'background-color: red'
d = {"A":c1,"B":c2,"C":c1,"D":c2}

df.style.apply(lambda x: x.index.map(d))

user_9332187 · Answer

We can manipulate the underlying HTML via looking at tags. One convenient way is with the BeautifulSoup library:

from bs4 import BeautifulSoup

# get the HTML representation
html = df.to_html()

# form the soup
soup = BeautifulSoup(html)

# the color categories
blues = {"A", "C"}
reds = {"B", "D"}

# for each possible "table header" tag...
for tag in soup.find_all("th"):
    # if tag's content is in `blues`...
    if tag.text in blues:
        # change the HTML style attribute accordingly
        tag["style"] = "background-color: blue;"
    # similar here..
    elif tag.text in reds:
        tag["style"] = "background-color: red;"

# get back the new HTML
new_html = str(soup)

Then, in an IPython notebook for example:

from IPython.display import HTML

HTML(new_html)

gives

user_7233155 · Answer

This feature is not currently available and the next release for this might be December 2021 (https://github.com/pandas-dev/pandas/pull/41893). However, you can easily work around this by using table styles. See my answer below:

df = pd.DataFrame([[1,2],[3,4],[5,6],[7,8]], index=["A", "B", "C", "D"])
green = [{'selector': 'th', 'props': 'background-color: green'}]
red = [{'selector': 'th', 'props': 'background-color: red'}]
df.style.set_table_styles({"A": green, "B": red, "C": green, "D": red}, axis=1)

Styling the background color of pandas index cell

3 Answers