Python Pandas - Return the rule code applied on the given DateOffset object

In Pandas, you can retrieve the rule code applied to a DateOffset object using the rule_code property. This property returns the frequency string used to create the offset.

Syntax

offset.rule_code

Example

Let's create a DateOffset and examine its rule code ?

from pandas.tseries.frequencies import to_offset
import pandas as pd

# Set the timestamp object in Pandas
timestamp = pd.Timestamp('2021-09-26 03:25:02.000045')

# Display the Timestamp
print("Timestamp...\n", timestamp)

# Create the DateOffset
# We are incrementing the months here using the "M" frequency
offset = to_offset("3M")

# Display the DateOffset
print("\nDateOffset...\n", offset)

# Display the Updated Timestamp
print("\nUpdated Timestamp...\n", timestamp + offset)

# Return the rule code of the frequency applied on the given DateOffset object
print("\nThe rule code of the DateOffset object...\n", offset.rule_code)

The output of the above code is ?

Timestamp...
 2021-09-26 03:25:02.000045

DateOffset...
 <3 * MonthEnds>

Updated Timestamp...
 2021-11-30 03:25:02.000045

The rule code of the DateOffset object..
 M

Different DateOffset Types

Let's explore rule codes for various DateOffset types ?

from pandas.tseries.frequencies import to_offset

# Create different types of DateOffsets
day_offset = to_offset("5D")
week_offset = to_offset("2W")
business_offset = to_offset("3B")
year_offset = to_offset("Y")

# Display their rule codes
print("Day offset rule code:", day_offset.rule_code)
print("Week offset rule code:", week_offset.rule_code)  
print("Business day offset rule code:", business_offset.rule_code)
print("Year offset rule code:", year_offset.rule_code)

Day offset rule code: D
Week offset rule code: W
Business day offset rule code: B
Year offset rule code: A

Key Points

• The rule_code returns the base frequency string without multipliers
• For "3M", the rule code is "M" (not "3M")
• This property is useful for identifying the frequency type of an offset
• Common rule codes include 'D' (day), 'W' (week), 'M' (month), 'A' (year), 'B' (business day)

Conclusion

The rule_code property provides the base frequency identifier for any DateOffset object. It's particularly useful when you need to programmatically determine the frequency type without the multiplier.