Checking if a datetimeindex falls into another list of dates and applying condition

Question

Using python, I've created a dataframe with a datetime index.

datetime_index = pd.date_range(start='2018-01-01', end='2019-12-31', freq='D')
df = pd.DataFrame({}, index=datetime_index)

Now I would like to be able to search through a list of dates, if the date in index is also in the list I've created, I would like a new variable df['fireworks'] to be 1, otherwise 0. I have tried creating a list like this:

fireworks = {'2018-07-04', '2018-07-05', '2018-04-13', '2018-04-18'}

I tried to accomplish this way:

df['fireworks'] = np.where(df.index==fireworks, 1, 0)

All the values of the newly created df['fireworks'] are still 0.

Thanks in advance to anyone helping me with this.

score 2 · Accepted Answer · answered Nov 05 '19 at 03:53

Use Series.isin:

datetime_index = pd.date_range(start='2018-01-01', end='2019-12-31', freq='D')
df = pd.DataFrame({}, index=datetime_index)

fireworks = {'2018-07-04', '2018-07-05', '2018-04-13', '2018-04-18'}

df['fireworks'] = np.where(df.index.isin(fireworks), 1, 0)

print (df[df["fireworks"].eq(1)])

#
            fireworks
2018-04-13          1
2018-04-18          1
2018-07-04          1
2018-07-05          1

Checking if a datetimeindex falls into another list of dates and applying condition

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