Posted on Categories Pragmatic Data Science, Pragmatic Machine Learning, TutorialsTags , , , , , Leave a comment on What is vtreat?

What is vtreat?

vtreat is a DataFrame processor/conditioner that prepares real-world data for supervised machine learning or predictive modeling in a statistically sound manner.

vtreat takes an input DataFrame that has a specified column called “the outcome variable” (or “y”) that is the quantity to be predicted (and must not have missing values). Other input columns are possible explanatory variables (typically numeric or categorical/string-valued, these columns may have missing values) that the user later wants to use to predict “y”. In practice such an input DataFrame may not be immediately suitable for machine learning procedures that often expect only numeric explanatory variables, and may not tolerate missing values.

To solve this, vtreat builds a transformed DataFrame where all explanatory variable columns have been transformed into a number of numeric explanatory variable columns, without missing values. The vtreat implementation produces derived numeric columns that capture most of the information relating the explanatory columns to the specified “y” or dependent/outcome column through a number of numeric transforms (indicator variables, impact codes, prevalence codes, and more). This transformed DataFrame is suitable for a wide range of supervised learning methods from linear regression, through gradient boosted machines.

The idea is: you can take a DataFrame of messy real world data and easily, faithfully, reliably, and repeatably prepare it for machine learning using documented methods using vtreat. Incorporating vtreat into your machine learning workflow lets you quickly work with very diverse structured data.

Worked examples can be found here.

For more detail please see here: arXiv:1611.09477 stat.AP (the documentation describes the R version, however all of the examples can be found worked in Python here).

vtreat is available as a Python/Pandas package, and also as an R package.

(logo: Julie Mount, source: “The Harvest” by Boris Kustodiev 1914)

Some operational examples can be found here.

Posted on Categories Administrativia, Pragmatic Data ScienceTags , , , , Leave a comment on Speaking at BARUG

Speaking at BARUG

We will be speaking at the Tuesday, September 3, 2019 BARUG. If you are in the Bay Area, please come see us.

Nina Zumel & John Mount
Practical Data Science with R

Practical Data Science with R (Zumel and Mount) was one of the first, and most widely-read books on the practice of doing Data Science using R. We have been working hard on an improved and revised 2nd edition of our book (coming out this Fall). The book reflects more experience with data science, teaching, and with R itself. We will talk about what direction we think the R community has been taking, how this affected the book, and what is new in the upcoming edition.

Posted on Categories OpinionTags , Leave a comment on Florence Nightingale, Data Scientist

Florence Nightingale, Data Scientist

Florence Nightingale, Data Scientist.

In 1858 Florence Nightingale published her now famous “rose diagram” breaking down causes of mortality.

Nightingale mortality

By w:Florence Nightingale (1820–1910). – [dead link], Public Domain, Link

For more please here.

Posted on Categories OpinionTags , , , , Leave a comment on PyCharm Video Review

PyCharm Video Review

My basic video review of the PyCharm integrated development environment for Python with Anaconda and Jupyter/iPython integration. I like the IDE extensions enough to pay for them early in my evaluation. Highly recommended for data science projects, at least try one of the open-source or the trial versions.

Posted on Categories OpinionTags , , 4 Comments on A Comment on Data Science Integrated Development Environments

A Comment on Data Science Integrated Development Environments

A point that differs from our experience struck us in the recent note regarding doing data science in Python:

A development environment [for Python] specifically tailored to the data science sector on the level of RStudio, for example, does not (yet) exist.

“What’s the Best Statistical Software? A Comparison of R, Python, SAS, SPSS and STATA” Amit Ghosh

Actually, Python has a large number of very capable integrated development environments, some of which are specifically tailored for data science. Please read on for a small list of tools, and my recommendations for a specific data science in Python toolchain.

Continue reading A Comment on Data Science Integrated Development Environments

Posted on Categories Opinion, StatisticsTags , , Leave a comment on Technical books are amazing opportunities

Technical books are amazing opportunities

Nina and I have been sending out drafts of our book Practical Data Science with R 2nd Edition for technical review. A few of the reviews came back from reviewers that described themselves with variations of:

Senior Business Analyst for COMPANYNAME. I have been involved in presenting graphs of data for many years.

To us this reads as somebody with deep experience, confidence, and bit of humility. They do something technical and valuable, but because they understand it they do not consider it to be arcane magic.

In this note we describe might can happen if such a person (or if a junior version of such a person) acquires 1 or 2 technical books.

Continue reading Technical books are amazing opportunities

Posted on Categories Administrativia, Practical Data Science, Pragmatic Data Science, Pragmatic Machine Learning, StatisticsTags , , , ,

Starting With Data Science: A Rigorous Hands-On Introduction to Data Science for Software Engineers

Starting With Data Science

A rigorous hands-on introduction to data science for software engineers.

Win Vector LLC is now offering a 4 day on-site intensive data science course. The course targets software engineers familiar with Python and introduces them to the basics of current data science practice. This is designed as an interactive in-person (not remote or video) course.

Continue reading Starting With Data Science: A Rigorous Hands-On Introduction to Data Science for Software Engineers

Posted on Categories Exciting Techniques, Opinion, TutorialsTags , ,

cdata Control Table Keys

In our cdata R package and training materials we emphasize the record-oriented thinking and how to design a transform control table. We now have an additional exciting new feature: control table keys.

The user can now control which columns of a cdata control table are the keys, including now using composite keys (that is keys that are spread across more than one column). This is easiest to demonstrate with an example.

Continue reading cdata Control Table Keys

Posted on Categories Administrativia, Opinion, Programming, StatisticsTags , , , , , 2 Comments on rquery: SQL from R

rquery: SQL from R

My BARUG rquery talk went very well, thank you very much to the attendees for being an attentive and generous audience.

IMG 5152

(John teaching rquery at BARUG, photo credit: Timothy Liu)

I am now looking for invitations to give a streamlined version of this talk privately to groups using R who want to work with SQL (with databases such as PostgreSQL or big data systems such as Apache Spark). rquery has a number of features that greatly improve team productivity in this environment (strong separation of concerns, strong error checking, high usability, specific debugging features, and high performance queries).

If your group is in the San Francisco Bay Area and using R to work with a SQL accessible data source, please reach out to me at, I would be honored to show your team how to speed up their project and lower development costs with rquery. If you are a big data vendor and some of your clients use R, I am especially interested in getting in touch: our system can help R users start working with your installation.