I'm getting an error AttributeError: 'list' object has no attribute 'rstrip' when trying to highlight using regex

Question

I'm fairly new to programming and trying to highlight specific cell within a dataframe but getting the error AttributeError: 'list' object has no attribute 'rstrip'. Not really sure how I can solve this.

data = {'country': ['US', 'US', 'China', 'India', 'US', 'India'], 
        'car_number': ['X123-00001C', 'X123-00002C', 'X123-00003C', 'X123-00004C', 'X123-00004', '']}  
  
df = pd.DataFrame(data)  

def color_in(val):
    highlight = 'background-color: orange;'
    default = ''
    if  str(~df['car_number'].str.match(r'^X\d\d\d[-]\d\d\d\d\d[C]$')) in val:
        return [highlight, default]
    else:
        return [default, default]

df.style.applymap(color_in, subset=['car_number'])

---------------------------------------------------------------------------
AttributeError                            Traceback (most recent call last)
/opt/conda/lib/python3.8/site-packages/IPython/core/formatters.py in __call__(self, obj)
    343             method = get_real_method(obj, self.print_method)
    344             if method is not None:
--> 345                 return method()
    346             return None
    347         else:

/opt/conda/lib/python3.8/site-packages/pandas/io/formats/style.py in _repr_html_(self)
    203         Hooks into Jupyter notebook rich display system.
    204         """
--> 205         return self.render()
    206 
    207     @doc(

/opt/conda/lib/python3.8/site-packages/pandas/io/formats/style.py in render(self, **kwargs)
    617         * table_attributes
    618         """
--> 619         self._compute()
    620         # TODO: namespace all the pandas keys
    621         d = self._translate()

/opt/conda/lib/python3.8/site-packages/pandas/io/formats/style.py in _compute(self)
    703         r = self
    704         for func, args, kwargs in self._todo:
--> 705             r = func(self)(*args, **kwargs)
    706         return r
    707 

/opt/conda/lib/python3.8/site-packages/pandas/io/formats/style.py in _applymap(self, func, subset, **kwargs)
    808         subset = non_reducing_slice(subset)
    809         result = self.data.loc[subset].applymap(func)
--> 810         self._update_ctx(result)
    811         return self
    812 

/opt/conda/lib/python3.8/site-packages/pandas/io/formats/style.py in _update_ctx(self, attrs)
    649                 if not c:
    650                     continue
--> 651                 c = c.rstrip(";")
    652                 if not c:
    653                     continue

AttributeError: 'list' object has no attribute 'rstrip'

Here is the error I am getting. I would like to highlight everything in the column that doesn't match the expression. Maybe there is a better way?

Answer 1

You can use

import pandas as pd
data = {'country': ['US', 'US', 'China', 'India', 'US', 'India'], 
        'car_number': ['X123-00001C', 'X123-00002C', 'X123-00003C', 'X123-00004C', 'X123-00004', '']}  

df = pd.DataFrame(data)
import re

def _color_orange(val):
    bgcolor = 'auto'
    color = 'auto'
    if re.match(r'^X\d{3}-\d{5}C$', val):
        bgcolor = 'orange'
        color = 'black'
    return f'background-color: {bgcolor}; color: {color}'

df = df.style.applymap(_color_orange, subset=["car_number"])

Output:

Here, the bgcolor and color variables are set to "auto" and "auto" by default.

Theif re.match(r'^X\d{3}-\d{5}C$', val) checks if the whole string starts with an X, then contains three digits, -, five digits, and C at the end. If it is true, the bgcolor and color variables are set to "orange" and "black".

The properties you need to change are called background-color (to set the background color) and color (for setting font color) (these are HTML attribute names in the Jupyter notebook).

The df.style.applymap(_color_orange, subset=["car_number"]) applies the coloring to the "car_number" column only.