Python Pandas - Extract the frequency object as a string from the DateTimeIndex

To extract the frequency object as a string from the DateTimeIndex, use the DateTimeIndex.freqstr property in Pandas. This property returns the frequency as a string representation, which is useful for displaying or storing the frequency information.

Creating a DateTimeIndex with Frequency

First, let's create a DateTimeIndex with a specific frequency ?

import pandas as pd

# Create DatetimeIndex with period 6 and frequency as D (daily)
# The timezone is Australia/Adelaide
datetimeindex = pd.date_range('2021-10-20 02:30:50', periods=6, tz='Australia/Adelaide', freq='D')

print("DateTimeIndex...")
print(datetimeindex)

DateTimeIndex...
DatetimeIndex(['2021-10-20 02:30:50+10:30', '2021-10-21 02:30:50+10:30',
               '2021-10-22 02:30:50+10:30', '2021-10-23 02:30:50+10:30',
               '2021-10-24 02:30:50+10:30', '2021-10-25 02:30:50+10:30'],
              dtype='datetime64[ns, Australia/Adelaide]', freq='D')

Extracting Frequency as String

Now let's extract the frequency information using different properties ?

import pandas as pd

datetimeindex = pd.date_range('2021-10-20 02:30:50', periods=6, tz='Australia/Adelaide', freq='D')

# Display frequency object
print("DateTimeIndex frequency object:")
print(datetimeindex.freq)

# Display frequency as string using freqstr
print("\nDateTimeIndex frequency as string:")
print(datetimeindex.freqstr)

DateTimeIndex frequency object:
<Day>

DateTimeIndex frequency as string:
D

Different Frequency Examples

Let's see how freqstr works with different frequency types ?

import pandas as pd

# Weekly frequency
weekly_index = pd.date_range('2021-01-01', periods=4, freq='W')
print("Weekly frequency string:", weekly_index.freqstr)

# Monthly frequency  
monthly_index = pd.date_range('2021-01-01', periods=4, freq='M')
print("Monthly frequency string:", monthly_index.freqstr)

# Hourly frequency
hourly_index = pd.date_range('2021-01-01', periods=4, freq='H')
print("Hourly frequency string:", hourly_index.freqstr)

# Business day frequency
business_index = pd.date_range('2021-01-01', periods=4, freq='B')
print("Business day frequency string:", business_index.freqstr)

Weekly frequency string: W-SUN
Monthly frequency string: M
Hourly frequency string: H
Business day frequency string: B

Conclusion

The freqstr property provides a simple way to get the frequency of a DateTimeIndex as a string. This is useful for debugging, logging, or when you need to store frequency information in a readable format.