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Category: Python

Appending Rows to a Pandas DataFrame

Matt Eland acquires some rows that fell off a truck:

Recently I was working on comparing the performance of different machine learning models and I wanted to add entries to a Pandas DataFrame as I evaluated each model. What I found was that adding new rows to a Pandas DataFrame was a little harder than I suspected and required some mild searching, so I wanted to preserve the two solutions I found here in case it helps someone else.

Read on for those two solutions, though as Matt points out, only one of them is a good solution.

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Bitemporal Modeling and Running Totals

John Mount solves a running total problem in Python:

An example of this is wanting to know any many reservations for a San Francisco Symphony concert scheduled for December 4th 2022 are known to have been made by October 22nd 2022. This could be used as part of an attendance demand model that is evaluated on October 22nd 2022. The “fifty-cent word” for this is “bitemporal” modeling or data.

As I read through the solution, my initial thought is that, if the data is in a relational database, a running total operation SUM(reservation_count) OVER (PARTITION BY target_date ORDER BY action_date ROWS BETWEEN UNBOUNDED PRECEDING TO CURRENT ROW) would form the basis of a solution. Still, this is an interesting exercise in translating a SQL operation into equivalent Python and just how much we get to take for granted.

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Fine-Tuning Hugging Face for Named Entity Recognition in Japanese

Tsuyoshi Matsuzaki tries out a named entity recognition project with the Hugging Face library:

Now a lot of AI companies (such as, OpenAI, NLP Cloud, Google, NVIDIA, etc) are providing pre-trained large language models including methods that tune to enable models trained. Among such tools and framework, HuggingFace is widely used and providing over 20,000 transformer-based models.

In this post, I’ll show you brief fine-tuned example of transformer models in Hugging Face for your beginning.
In the last part of this post, I’ll also optimize training with DeepSpeed which is well integrated with HuggingFace transformers.

Click through for the results of this analysis.

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Working with Transformer Models for Machine Translation

Stefania Cristina continues a series on transformer models. First up is plotting loss curves:

We have previously seen how to train the Transformer model for neural machine translation. Before moving on to inferencing the trained model, let us first explore how to modify the training code slightly, in order to be able to plot the training and validation loss curves that can be generated during the learning process. 

The training and validation loss values provide important pieces of information, because they allow us to have a better insight on how the learning performance is changing over the number of epochs, and help us diagnose any problems with learning that can lead to an underfit or an overfit model. They will also inform us about the epoch at which to use the trained model weights at the inferencing stage.

Then we get to try it out:

We have seen how to train the Transformer model on a dataset of English and German sentence pairs, as well as how to plot the training and validation loss curves in order to diagnose the model’s learning performance and decide at which epoch to inference the trained model. We are now ready to inference the trained Transformer model for the purpose of translating an input sentence.

In this tutorial, you will discover how to inference the trained Transformer model for neural machine translation. 

Click through for the results and to see exactly why there’s so much computational effort dumped into high-end trained models.

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Training a Language Transformer Model

Stefania Cristina continues a series on building a language transformer:

We have put together the complete Transformer model, and now we are ready to train it for neural machine translation. We shall be making use of a training dataset for this purpose, which contains short English and German sentence pairs. We will also be revisiting the role of masking in computing the accuracy and loss metrics during the training process. 

In this tutorial, you will discover how to train the Transformer model for neural machine translation. 

Read on for the process, including a lot of code.

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Kernel SHAP in R and Python

Michael Mayer and Christian Lorentzen team up:

SHAP is one of the most used model interpretation technique in Machine Learning. It decomposes predictions into additive contributions of the features in a fair way. For tree-based methods, the fast TreeSHAP algorithm exists. For general models, one has to resort to computationally expensive Monte-Carlo sampling or the faster Kernel SHAP algorithm. Kernel SHAP uses a regression trick to get the SHAP values of an observation with a comparably small number of calls to the predict function of the model. Still, it is much slower than TreeSHAP.

Read on to see how to do this in both R and Python. With libraries the way they are, the code is very similar and the results are basically the same.

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Finding Near-Duplicates in a Corpus

Estelle Wang de-dupes text data:

Building a large high-quality corpus for Natural Language Processing (NLP) is not for the faint of heart. Text data can be large, cumbersome, and unwieldy and unlike clean numbers or categorical data in rows and columns, discerning differences between documents can be challenging. In organizations where documents are shared, modified, and shared again before being saved in an archive, the problem of duplication can become overwhelming.

To find exact duplicates, matching all string pairs is the simplest approach, but it is not a very efficient or sufficient technique. Using the MD5 or SHA-1 hash algorithms can get us a correct outcome with a faster speed, yet near-duplicates would still not be on the radar. Text similarity is useful for finding files that look alike. There are various approaches to this and each of them has its own way to define documents that are considered duplicates. Furthermore, the definition of duplicate documents has implications for the type of processing and the results produced. Below are some of the options.

Click through for solutions in SAS.

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Deploying a Streamlit App to RStudio Connect

Parisa Gregg wraps up a series:

RStudio Connect is a platform which is well known for providing the ability to deploy and share R applications such as Shiny apps and Plumber APIs as well as plots, models and R Markdown reports. However, despite the name, it is not just for R developers (hence their recent announcement). RStudio Connect also supports a growing number of Python applications, API services including Flask and FastAPI and interactive web based apps such as Bokeh and Streamlit.

In this post we will look at how to deploy a Streamlit application to RStudio Connect. Streamlit is a framework for creating interactive web apps for data visualisation in Python. It’s API makes it very easy and quick to display data and create interactive widgets from just a regular Python script.

Click through for the step-by-step process.

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RStudio Connect and Python’s FastAPI

Parisa Gregg continues a series on RStudio Connect and Python:

FastAPI is a light web framework and as you can probably tell by the name, it’s fast. It provides a similar functionality to Flask in that it allows the building of web applications and APIs, however it is newer and uses the ASGI (Asynchronous Server Gateway Interface) framework. One of the nice features of FastAPI is it is built on OpenAPI and JSON Schema standards which means it has the ability to provide automatic interactive API documentation with SwaggerUI. You also get validation for most Python data types with Pydantic. FastAPI is therefore another popular choice for data scientists when creating APIs to interact with and visualize data.

In this blog post we will go through how to deploy a simple machine learning API to RStudio Connect.

I’ve taken pretty well to FastAPI for rapid API development. I haven’t had to worry about scaling it out too much, so I’m not sure how well that works in practice. Still, for single-user or few-user apps, FastAPI definitely works well.

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Developing a Flask App with RStudio Connect

Parisa Gregg crosses the language barrier:

One of the Python applications you can deploy to RStudio Connect is Flask. Flask is a WSGI (Web Server Gateway Interface) web application framework and provides a Python interface to enable the building of web APIs. It is useful to data scientists, for example for building interactive web dashboards and visualisations of data, as well as APIs for machine learning models. Deploying a Flask app to a publishing platform such as RStudio Connect means it can then be used from anywhere and can be easily shared with clients.

This blog post focuses on how to deploy a Flask app to RStudio Connect. We will use a simple example but won’t go into detail on how to create Flask apps. If you are getting started in Flask you may find this tutorial useful.

Read on for a demo.

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