Highlight cell on condition

Question

I\'m trying to highlight all cells that are before the current date. However I am highlighting all cells instead of just the old dates.

import pandas as pd
from         


        

Answer 1

Idea is create new DataFrame filled by styles by condition with Styler.apply, for set rows by conditions is used numpy.where:

def expired(x):
    c1 = 'background-color: red'
    c2 = 'background-color: green'

    df1 = pd.DataFrame('', index=x.index, columns=x.columns)
    m = x['Expiration Date'] < today
    df1['Expiration Date'] = np.where(m, c1, c2)
    return df1

df.style.apply(expired, axis=None)

If coloring all rows by condition use DataFrame.mask:

def expired(x):
    c1 = 'background-color: red'
    c2 = 'background-color: green'

    df1 = pd.DataFrame(c1, index=x.index, columns=x.columns)
    m = x['Expiration Date'] < today
    df1 = df1.mask(m, c2)
    return df1