Python Pandas - Get the weekmask applied on the CustomBusinessDay offset

The weekmask property in Pandas allows you to retrieve the custom business days pattern applied to a CustomBusinessDay offset. This is useful for understanding which days of the week are considered valid business days in your custom offset.

What is CustomBusinessDay?

CustomBusinessDay is a DateOffset subclass that represents custom business days while excluding holidays. Unlike standard business days (Mon-Fri), you can specify your own pattern of valid business days using a weekmask.

Creating a CustomBusinessDay with Weekmask

First, let's create a timestamp and a CustomBusinessDay offset with a custom weekmask ?

import pandas as pd

# Set the timestamp object
timestamp = pd.Timestamp('2021-10-22 03:10:35')
print("Original Timestamp:", timestamp)

# Create CustomBusinessDay with custom weekmask (Mon, Tue, Wed, Fri only)
cbdOffset = pd.tseries.offsets.CustomBusinessDay(n=4, weekmask='Mon Tue Wed Fri')
print("CustomBusinessDay Offset:", cbdOffset)

Original Timestamp: 2021-10-22 03:10:35
CustomBusinessDay Offset: <4 * CustomBusinessDays>

Getting the Weekmask Property

Use the weekmask property to retrieve the business days pattern applied to the offset ?

import pandas as pd

timestamp = pd.Timestamp('2021-10-22 03:10:35')
cbdOffset = pd.tseries.offsets.CustomBusinessDay(n=4, weekmask='Mon Tue Wed Fri')

# Get the weekmask applied
print("Weekmask:", cbdOffset.weekmask)

# Add offset to timestamp
updated_timestamp = timestamp + cbdOffset
print("Updated Timestamp:", updated_timestamp)

# Other useful properties
print("Frequency string:", cbdOffset.freqstr)
print("Number of increments:", cbdOffset.n)

Weekmask: Mon Tue Wed Fri
Updated Timestamp: 2021-10-29 03:10:35
Frequency string: 4C
Number of increments: 4

Complete Example

Here's a comprehensive example showing how to work with CustomBusinessDay and retrieve its weekmask ?

import pandas as pd

# Set the timestamp object in Pandas
timestamp = pd.Timestamp('2021-10-22 03:10:35')

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

# Create the CustomBusinessDay Offset
# CustomBusinessDay is the DateOffset subclass representing custom business days excluding holidays
# Weekmask of valid business days
cbdOffset = pd.tseries.offsets.CustomBusinessDay(n=4, weekmask='Mon Tue Wed Fri')

# Display the CustomBusinessDay Offset
print("\nCustomBusinessDay Offset...\n", cbdOffset)

# Add the offset to the Timestamp and display the Updated Timestamp
print("\nUpdated Timestamp...\n", timestamp + cbdOffset)

# Return frequency applied on the given CustomBusinessDay Offset object as a string
print("\nFrequency applied on the given CustomBusinessDay Offset object...\n", cbdOffset.freqstr)

# return the count of increments on the given CustomBusinessDay object
print("\nThe count of increments on the CustomBusinessDay object..\n", cbdOffset.n)

# display the weekmask
print("\nThe weekmask on the CustomBusinessDay object..\n", cbdOffset.weekmask)

Timestamp...
 2021-10-22 03:10:35

CustomBusinessDay Offset...
 <4 * CustomBusinessDays>

Updated Timestamp...
 2021-10-29 03:10:35

Frequency applied on the given CustomBusinessDay Offset object...
 4C

The count of increments on the CustomBusinessDay object..
 4

The weekmask on the CustomBusinessDay object..
 Mon Tue Wed Fri

Key Properties

Conclusion

Use the weekmask property to retrieve the custom business days pattern from a CustomBusinessDay offset. This property returns a string showing which days are considered valid business days in your custom offset configuration.