Python Pandas - Create a PeriodIndex and get the day of the year

To create a PeriodIndex, use the pandas.PeriodIndex() method. Get the day of the year using the PeriodIndex.dayofyear property.

At first, import the required libraries −

import pandas as pd

Create a PeriodIndex object. PeriodIndex is an immutable ndarray holding ordinal values indicating regular periods in time. We have set the frequency using the "freq" parameter −

periodIndex = pd.PeriodIndex(['2018-07-25', '2019-10-30', '2020-11-20',
'2021-09-15', '2022-03-12', '2023-06-18'], freq="D")

Display PeriodIndex object −

print("PeriodIndex...\n", periodIndex)

Display day of the year from the PeriodIndex object −

print("\nDays of the year from the PeriodIndex...\n", periodIndex.dayofyear)

Example

Following is the code −

import pandas as pd

# Create a PeriodIndex object
# PeriodIndex is an immutable ndarray holding ordinal values indicating regular periods in time
# We have set the frequency using the "freq" parameter
periodIndex = pd.PeriodIndex(['2018-07-25', '2019-10-30', '2020-11-20',
'2021-09-15', '2022-03-12', '2023-06-18'], freq="D")

# Display PeriodIndex object
print("PeriodIndex...\n", periodIndex)

# Display PeriodIndex frequency
print("\nPeriodIndex frequency...\n", periodIndex.freq)

# Display day from the PeriodIndex object
print("\nThe number of days from the PeriodIndex...\n", periodIndex.day)
# Display day of the year from the PeriodIndex object
print("\nDays of the year from the PeriodIndex...\n", periodIndex.dayofyear)

Output

This will produce the following code −

PeriodIndex...
PeriodIndex(['2018-07-25', '2019-10-30', '2020-11-20', '2021-09-15', '2022-03-12', '2023-06-18'],
dtype='period[D]')

PeriodIndex frequency...
<Day>

The number of days from the PeriodIndex...
Int64Index([25, 30, 20, 15, 12, 18], dtype='int64')

Days of the year from the PeriodIndex...
Int64Index([206, 303, 325, 258, 71, 169], dtype='int64')