In this tutorial, we will learn about the toordinal() method of datetime module in Python. The toordinal() method is a function in Python’s datetime module, not specifically in pandas. It converts a datetime.date object to an ordinal number, which is the number of days since January 1, 0001 (the start of the Gregorian calendar). This number is useful for certain types of date arithmetic and comparisons.
toordinal() method in Python:
In Python, you can use toordinal() with a date object from the datetime module like this:
import datetime
# Create a date object
date_obj = datetime.date(2023, 8, 8)
# Convert to ordinal
ordinal_number = date_obj.toordinal()
print("Ordinal number of date ",date_obj," is:", ordinal_number)
# Create a another date object
date_obj = datetime.date(2024, 2, 7)
# Convert to ordinal
ordinal_number = date_obj.toordinal()
print("Ordinal number of date ",date_obj," is:", ordinal_number)Output:
Ordinal number of date 2023-08-08 is: 738740
Ordinal number of date 2024-02-07 is: 738923
toordinal() method in Pandas:
Since pandas builds heavily on top of datetime, you can convert using pandas library.Timestamp objects (or date columns in a DataFrame) to their ordinal equivalents using the same method.
import pandas as pd
# Create a pandas Series with datetime objects
dates = pd.Series(pd.to_datetime(['2023-08-08', '2024-01-01', '2025-12-25']))
# Convert to ordinal using the apply function
ordinal_dates = dates.apply(lambda x: x.toordinal())
print(ordinal_dates)This would output a pandas Series where each date is represented by its corresponding ordinal number.
Output:
0 738740
1 738886
2 739610
dtype: int64
Question and Answer:
Q1. what is use of toordinal() method in python?
Answer – The toordinal() function in Python converts a datetime.date object to an integer representing the number of days since January 1, 0001. This integer format simplifies date arithmetic, such as calculating the number of days between two dates, and makes comparisons straightforward by allowing direct numerical comparison. It also facilitates sorting and integration with systems that use integer date representations, providing a consistent and efficient way to handle dates in numerical operations.
Q2. how can toordinal method is useful in some Machine learning algortihm?
Answer – The toordinal() method is useful in Machine Learning (ML) algorithms by converting dates into integer values, which are easier for models to process. This transformation allows date features to be used directly as numerical inputs, facilitating feature engineering and integration into models. It simplifies temporal analysis by quantifying time intervals, making it easier to capture trends and patterns. Additionally, working with integers can improve computational efficiency and model performance by reducing the complexity of date handling.