Formatting numbers after coloring a dataframe using Styler

Question

I created a DataFrame in pandas for which I want to color the cells using a color index (low values red, high values green). I succeeded in doing so, however the coloring prevents me to format the cells.

import pandas as pd

df = pd.DataFrame({'a': [0.5,1.5, 5],
                   'b': [2, 3.5, 7] })

df = df.style.background_gradient(cmap='RdYlGn')
df

which returns

However, when I try to use df.round(2) for example to format the numbers, the following error pops up:

AttributeError: 'Styler' object has no attribute 'round'

jkr · Accepted Answer · 2023-06-05 16:11:19Z

11

Take a look at the pandas styling guide. The df.style property returns a Styler instance, not a dataframe. From the examples in the pandas styling guide, it seems like dataframe operations (like rounding) are done first, and styling is done last. There is a section on precision in the pandas styling guide. That section proposes three different options for displaying precision of values.

import pandas as pd

df = pd.DataFrame({'a': [0.5,1.5, 5],
                   'b': [2, 3.5, 7] })

# Option 1. Round before using style.
style = df.round(2).style.background_gradient(cmap='RdYlGn')
style

# Option 2. Use option_context to set precision.
with pd.option_context('display.precision', 2):
    style = df.style.background_gradient(cmap='RdYlGn')
style

# Option 3. Use .format() method of styler.
style = df.style.format(precision=2).background_gradient(cmap='RdYlGn')
style

edited Jun 5, 2023 at 16:11

answered Feb 18, 2021 at 14:42

jkr

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5 Comments

gardangerous Over a year ago

Option 1 doesn't work for me, but 2 and 3 are exactly what I was looking for. Thanks a lot!

jkr Over a year ago

Glad to hear it. If this answer solved your problem, please click the green check mark to mark it as correct.

Alex M Over a year ago

Method '.set_precision' is deprecated in the current Pandas release (v1.3.1). The new method passes float precision through '.format(precision = 2)'. However, I had a problem with this and had to revert to previous Pandas version. I tried various methods as stated in the docs, but I couldn't get it to work. Perhaps an inconsistency with the older Python version I use 3.7.7.

jkr Over a year ago

thanks @TrentonMcKinney I have updated the answer to fix this.

Trenton McKinney Over a year ago

You might want to just delete 3. As the other answer already covers .format. In any case, also update the docstring for #3 if you leave it.

Hamzah Al-Qadasi · Accepted Answer · 2022-12-13 17:05:47Z

1

This works with me:

stylish_df = df.style.background_gradient(cmap='RdYlGn').format(precision=2)

answered Dec 13, 2022 at 17:05

Hamzah Al-Qadasi

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