Скачать или смотреть Simplifying Data Frame Mode Assignment in Pandas: No More Nested Loops!

Discover an efficient way to assign train, valid, and test modes in your pandas DataFrame without using complex loops.
---
This video is based on the question https://stackoverflow.com/q/75751384/ asked by the user 'Dang' ( https://stackoverflow.com/u/20923866/ ) and on the answer https://stackoverflow.com/a/75751627/ provided by the user 'ziying35' ( https://stackoverflow.com/u/16755671/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

Visit these links for original content and any more details, such as alternate solutions, latest updates/developments on topic, comments, revision history etc. For example, the original title of the Question was: Get train/valid/test index with sequence from pandas dataframe

Also, Content (except music) licensed under CC BY-SA https://meta.stackexchange.com/help/l...
The original Question post is licensed under the 'CC BY-SA 4.0' ( https://creativecommons.org/licenses/... ) license, and the original Answer post is licensed under the 'CC BY-SA 4.0' ( https://creativecommons.org/licenses/... ) license.

If anything seems off to you, please feel free to write me at vlogize [AT] gmail [DOT] com.
---
Simplifying Data Frame Mode Assignment in Pandas: No More Nested Loops!

When working with data in Python, pandas is a go-to library for many data analysts and scientists. However, certain tasks can become cumbersome, especially when trying to categorize data into different sets. Today, we're focusing on a common problem: how to efficiently categorize sequences into training, validation, and testing modes within a pandas DataFrame.

The Challenge

Imagine you have a DataFrame representing user interactions, with each user having a different number of recorded sequences (cnt_seq). You want to categorize these sequences into three distinct groups:

Train: The sequences that will be used for training the model.

Valid: The last sequence of each user, designated for validation.

Test: The second last sequence before the valid one, which will be used for testing the model.

This might seem simple at first, but traditional methods often involve nested loops, which can be inefficient. Here’s a look at how the task was originally attempted:

Original Code using For Loops

[[See Video to Reveal this Text or Code Snippet]]

While this approach works, it involves looping through the sequences for each user, which is not ideal, especially for larger datasets.

The Simplified Solution

Fortunately, there is a more efficient way to achieve this using vectorized operations in pandas. Here’s the new approach:

Step-by-Step Breakdown

Create the DataFrame: Begin by defining your user interaction data.

Group by User: Calculate the maximum sequence for each user to easily distinguish the test and validation sequences.

Assign Modes Efficiently: Use the np.select function to assign modes based on conditions, which eliminates the need for multiple loops.

Here's how you can implement this solution:

[[See Video to Reveal this Text or Code Snippet]]

Benefits of the Simplified Code

Efficiency: The vectorized approach performs better, especially with large datasets, avoiding the overhead of multiple Python loops.

Readability: The use of np.select simplifies understanding the conditions for assigning modes.

Maintenance: Fewer lines of code mean it's easier to maintain and update.

Conclusion

By leveraging pandas and NumPy's capabilities, we can dramatically simplify our data processing tasks. The example provided illustrates how to effectively assign train, valid, and test modes with clean and efficient code. Explore more such opportunities to improve your data processing with these efficient techniques!

Happy coding!