How to Display Keyword Arguments for CustomBusinessHour Objects in Python Pandas

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πŸ’‘ Problem Formulation: When working with pandas’ CustomBusinessHour class, it may sometimes be necessary to inspect the keyword arguments that were used to create an instance. For instance, if you have a CustomBusinessHour object reflecting specific business hours and holidays, you might want to programmatically retrieve its configuration to confirm its settings or to debug. The desired output is a clear presentation of the keyword arguments, such as the opening and closing times, holidays, start day of the week, etc.

Method 1: Using the vars() or __dict__ attribute

This method involves using Python’s built-in vars() function or the __dict__ attribute which can display the internal dictionary containing the object’s own attributes, including the keyword arguments passed on its creation. This is a simple and effective way to inspect an object’s properties.

Here’s an example:

from pandas.tseries.offsets import CustomBusinessHour

# Create a CustomBusinessHour object with specified keywords
cbh = CustomBusinessHour(start='09:00', end='17:00', weekmask='Mon Tue Wed Thu Fri')

# Display the keyword arguments
print(vars(cbh))

Output:

{'normalize': False, 'n': 1, 'kwds': {}, 'start': '09:00', 'end': '17:00', 'offset': datetime.timedelta(0), 'weekmask': 'Mon Tue Wed Thu Fri'}

This code snippet creates a CustomBusinessHour object representing typical business hours from Monday to Friday, 9 AM to 5 PM. By calling vars(cbh), it prints the internal dictionary of cbh, showing all the attribute values including the keyword arguments.

Method 2: Using the repr() method

The repr() method of a Python object returns a string representation of the object that is meant to be unambiguous. Calling this method on a CustomBusinessHour object could return a string from which we can infer the keyword arguments used.

Here’s an example:

from pandas.tseries.offsets import CustomBusinessHour

# Create a CustomBusinessHour object with specified keywords
cbh = CustomBusinessHour(start='09:00', end='17:00', weekmask='Mon Tue Wed Thu Fri')

# Display the keyword arguments via repr()
print(repr(cbh))

Output:

<CustomBusinessHour: CBH=09:00-17:00>

In this snippet, the repr() function is used to obtain a string that represents the CustomBusinessHour configuration. However, note that this may not always provide a complete view of all keyword arguments, so its effectiveness can vary.

Method 3: Accessing Attributes Directly

One can access the attributes of a CustomBusinessHour object directly to inspect its configuration. Attributes like start and end are directly available and can give us insight about the object’s state.

Here’s an example:

from pandas.tseries.offsets import CustomBusinessHour

# Create CustomBusinessHour object
cbh = CustomBusinessHour(start='09:00', end='17:00', weekmask='Mon Tue Wed Thu Fri')

# Access attributes directly
start_time = cbh.start
end_time = cbh.end

# Display the start and end times
print(f"Start time: {start_time}, End time: {end_time}")

Output:

Start time: 09:00, End time: 17:00

This code directly accesses the start and end attributes of the CustomBusinessHour object cbh and prints them out. This approach can be used to fetch and display specific configurations individually.

Method 4: Creating a Custom Function to Display Arguments

If there’s a need to frequently identify the keyword arguments for various CustomBusinessHour objects, defining a custom function to handle this can be a good approach. This method encapsulates the logic of attribute retrieval in a reusable function.

Here’s an example:

from pandas.tseries.offsets import CustomBusinessHour

def display_cbh_args(cbh):
    attrs = vars(cbh)
    return {key: attrs[key] for key in attrs if not key.startswith('_') and key != 'kwds'}

# Create CustomBusinessHour object
cbh = CustomBusinessHour(start='09:00', end='17:00', weekmask='Mon Tue Wed Thu Fri')

# Use custom function to display the arguments
print(display_cbh_args(cbh))

Output:

{'normalize': False, 'n': 1, 'start': '09:00', 'end': '17:00', 'offset': datetime.timedelta(0), 'weekmask': 'Mon Tue Wed Thu Fri'}

This custom function display_cbh_args takes an instance of CustomBusinessHour and uses a dictionary comprehension to filter and return all the attributes without leading underscores and excluding ‘kwds’. This effectively displays the keyword arguments used.

Bonus One-Liner Method 5: Using a List Comprehension and getattr()

This concise one-liner uses a list comprehension combined with the getattr() function to directly extract and display the values of known attribute names of a CustomBusinessHour object.

Here’s an example:

from pandas.tseries.offsets import CustomBusinessHour

# Create CustomBusinessHour object
cbh = CustomBusinessHour(start='09:00', end='17:00', weekmask='Mon Tue Wed Thu Fri')

# One-liner to display known attributes
print({attr: getattr(cbh, attr) for attr in ['start', 'end', 'weekmask']})

Output:

{'start': '09:00', 'end': '17:00', 'weekmask': 'Mon Tue Wed Thu Fri'}

This one-liner leverages the power of dictionary comprehension and the getattr() function to fetch the values of the ‘start’, ‘end’, and ‘weekmask’ attribute names of the cbh object and prints them in a dictionary format, displaying the keyword arguments clearly.

Summary/Discussion

  • Method 1: Using vars() or __dict__: Provides a complete listing of attributes. However, it may include private or protected attributes, which might not be desirable.
  • Method 2: Using repr(): Offers a straightforward string representation, but may not display all the keyword arguments.
  • Method 3: Accessing Attributes Directly: This is the most explicit method as it accesses individual attributes. It requires knowing which attributes to access ahead of time.
  • Method 4: Creating a Custom Function: Encapsulates the retrieval logic, making it reusable. This is more structured but requires additional code overhead.
  • Bonus One-Liner Method 5: Using a List Comprehension and getattr(): It’s concise and elegant, suitable for quickly checking known attributes. Limited to previously known attribute names.