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Category: Python

PyODBC vs C# ODBC Performance Differences

Jose Manuel Jurado Diaz explains a performance difference:

A customer asked today, why using ODBC Driver 17 for SQL Server in Python with PYODBC we have a slightly difference in terms of time taken if we compare with C# System.Data.Odbc. Following, I would like to share my lesson learned about it.

Read on for Jose’s explanation. My short version is, it seems particularly important when using the Python ODBC driver to write the exact query you want rather than a SELECT * or query which returns rows/columns you don’t need.

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Custom Model Evaluation Metrics with MLflow

Mark Zhang shows off a new bit of functionality in MLflow:

According to an internal customer survey, 75% of respondents say they frequently or always use specialized, business-focused metrics in addition to basic ones like accuracy and loss. Data scientists often utilize these custom metrics as they are more descriptive of business objectives (e.g. conversion rate), and contain additional heuristics not captured by the model prediction itself.

In this blog, we introduce an easy and convenient way of evaluating MLflow models on user-defined custom metrics. With this functionality, a data scientist can easily incorporate this logic at the model evaluation stage and quickly determine the best-performing model without further downstream analysis

Click through to see how to use built-in metrics but also how to create your own.

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Iteratively Tuning Graph Neural Networks

Luis Bermudez takes us through the process of tuning one flavor of neural network:

We made our own implementations of OGB leaderboard entries for two popular GNN frameworks: GraphSAGE and a Relational Graph Convolutional Network (RGCN). We then designed and executed an iterative experimentation approach for hyperparameter tuning where we seek a quality model that takes minimal time to train. We define quality by running an unconstrained performance tuning loop, and use the results to set thresholds in a constrained tuning loop that optimizes for training efficiency.

Read on to see how they did it.

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R and Python Interop via Reticulate

Fabian Scheler combines R and Python:

I am way more experienced with R than with Python and prefer to code in this language when possible. This applies, especially when it is about visualizations. Plotly and ggplot2 are fantastic packages that provide a lot of flexibility. However, every language has its limitations, and the best results stem from their efficient combination.

This week, I created the candlestick below, and I think it’s an excellent case study to illustrate a few things:

Read on to learn more about using reticulate to execute Python code and interact with the results in R.

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Logging in Python

Daniel Chung shows off the logging module in Python:

Note that now all five messages were output, so the default level that the root logger logs is now “DEBUG.” The log record attributes (such as %(asctime)s) that can be used to format the output can be found in the logging documentation.

Although there is a default logger, we usually want to make and use other loggers that can be configured separately. This is because we may want a different severity level or format for different loggers. 

Next on the todo list is to implement the Reader monad to hide that logging deeper in your code base so that you a) don’t need to see logging code everywhere, and b) don’t forget to include logging in some function.

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Topic Modeling with Python

Sanil Mhatre takes us through topic modeling:

Topic modeling is a powerful Natural Language Processing technique for finding relationships among data in text documents. It falls under the category of unsupervised learning and works by representing a text document as a collection of topics (set of keywords) that best represent the prevalent contents of that document. This article will focus on a probabilistic modeling approach called Latent Dirichlet Allocation (LDA), by walking readers through topic modeling using the team health demo dataset. Demonstrations will use Python and a Jupyter notebook running on Anaconda. Please follow instructions from the “Initial setup” section of the previous article to install Anaconda and set up a Jupyter notebook.

The second article of this series, Text Mining and Sentiment Analysis: Power BI Visualizations, introduced readers to the Word Cloud, a common technique to represent the frequency of keywords in a body of text. Word Cloud is an image composed of keywords found within a body of text, where the size of each word indicates its frequency in that body of text. This technique is limited in its ability to discover underlying topics and themes in the text, because it only relies on the frequency of keywords to determine their popularity. Topic modeling overcomes these limitations and uncovers deeper insights from text data using statistical modeling for discovering the topics (collection of words) that occur in text documents.

Read on for an informative article with plenty of code.

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Data Profiling in Python

Brendan Tierney uses Python to look at some data:

One of the most common, and sometimes boring, task when working with datasets is writing some code to profile the data. Most data scientists will have built a set of tools/scripts to help them with this regular and slightly boring task. As with most IT tasks we should be trying to automate what we can, to allow us to spend more time on more important tasks, such as deriving insights and delivering value to the business, instead of repeatedly writing code to produce various statistics about the data and drawing pretty pictures.

I’ve written previously about automating and using some data profiling libraries to help us with this task. There are lots of packages available on pypi.og and on GitHub. Below I give examples of 5 Python Data Profiling libraries, with links to their GitHubs.

Brendan includes some good examples of libraries here so check it out.

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Data Visualization in Python

Mehreen Saeed uses a few data visualization libraries in Python:

Data visualization is an important aspect of all AI and machine learning applications. You can gain key insights of your data through different graphical representations. In this tutorial, we’ll talk about a few options for data visualization in Python. We’ll use the MNIST dataset and the Tensorflow library for number crunching and data manipulation. To illustrate various methods for creating different types of graphs, we’ll use the Python’s graphing libraries namely matplotlib, Seaborn and Bokeh.

Bokeh results can look really nice, although it does feel like it requires a lot more developer time and effort to get it right. Click through for examples of each of the three libraries.

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