Calculate TimedeltaArray of Difference Between Index Values in Pandas

To calculate TimedeltaArray of difference between index values and index converted to PeriodArray at specified freq, use the datetimeindex.to_perioddelta() method. Set the frequency using the freq parameter.

At first, import the required libraries −

import pandas as pd

Create a DatetimeIndex with period 7 and frequency as Y i.e. year −

datetimeindex = pd.date_range('2021-10-18 07:20:32.261811624', periods=5, freq='2Y')

Display DateTimeIndex −

print("DateTimeIndex...\n", datetimeindex)

Calculate TimedeltaArray of difference between index values and index converted to PeriodArray. We have set the Period frequency using the "freq" parameter with value 'M' −

print("\nConvert DateTimeIndex to PeriodDelta...\n",
datetimeindex.to_perioddelta(freq='M'))

Example

Following is the code −

import pandas as pd

# DatetimeIndex with period 7 and frequency as Y i.e. year
# timezone is Australia/Adelaide
datetimeindex = pd.date_range('2021-10-18 07:20:32.261811624', periods=5, freq='2Y')

# display DateTimeIndex
print("DateTimeIndex...\n", datetimeindex)

# display DateTimeIndex frequency
print("DateTimeIndex frequency...\n", datetimeindex.freq)

# Convert DateTimeIndex to Period
# We have set the frequency as Month using the "freq" parameter with value 'M'
print("\nConvert DateTimeIndex to Period...\n",
datetimeindex.to_period(freq='M'))

# Calculate TimedeltaArray of difference between index values and index converted to PeriodArray
# We have set the Period frequency using the "freq" parameter with value 'M'
print("\nConvert DateTimeIndex to PeriodDelta...\n",
datetimeindex.to_perioddelta(freq='M'))

Output

This will produce the following code −

DateTimeIndex...
DatetimeIndex(['2021-12-31 07:20:32.261811624',
'2023-12-31 07:20:32.261811624',
'2025-12-31 07:20:32.261811624',
'2027-12-31 07:20:32.261811624',
'2029-12-31 07:20:32.261811624'],
dtype='datetime64[ns]', freq='2A-DEC')
DateTimeIndex frequency...
<2 * YearEnds: month=12>

Convert DateTimeIndex to Period...
PeriodIndex(['2021-12', '2023-12', '2025-12', '2027-12', '2029-12'], dtype='period[M]')

Convert DateTimeIndex to PeriodDelta...
TimedeltaIndex(['30 days 07:20:32.261811624', '30 days 07:20:32.261811624',
'30 days 07:20:32.261811624', '30 days 07:20:32.261811624',
'30 days 07:20:32.261811624'],
dtype='timedelta64[ns]', freq=None)