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 firstname.lastname@example.org, 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.
I would like to thank LinkedIn for letting me speak with some of their data scientists and analysts.
John Mount discussing
SQLgeneration at LinkedIn.
If you have a group using
R at database or
Spark scale, please reach out ( jmount at win-vector.com ). We (Win-Vector LLC) have some great new tools I’d love to speak on and share. I’d love an invite, especially if your group is in the San Francisco Bay Area.
Note: we also now have a 1/2 to 1 day on-site “Spark for R Users” training offering. Again, please reach out if your team is interested.
In this note I want to share some exciting and favorable initial rquery benchmark timings.
I want to discuss a nice series of figures used to teach relational join semantics in R for Data Science by Garrett Grolemund and Hadley Wickham, O’Reilly 2016. Below is an example from their book illustrating an inner join:
Please read on for my discussion of this diagram and teaching joins. Continue reading Visualizing relational joins
We are very sorry for any confusion, trouble, or wasted effort bringing in Java software (something we are very familiar with, but forget not everybody uses) has caused readers. Also, database adapters for R have greatly improved, so we feel more confident depending on them alone. Practical Data Science with R remains an excellent book and a good resource to learn from that we are very proud of and fully support (hence errata). Continue reading Practical Data Science with R errata update: Java SQLScrewdriver replaced by R procedures and article
replyr is an
R package that contains extensions, adaptions, and work-arounds to make remote
dplyr data sources (including big data systems such as
Spark) behave more like local data. This allows the analyst to more easily develop and debug procedures that simultaneously work on a variety of data services (in-memory
Spark2 currently being the primary supported platforms).
Consider the common following problem: compute for a data set (say the infamous
iris example data set) per-group ranks. Suppose we want the rank of
Sepal.Lengths on a per-
Species basis. Frankly this is an “ugh” problem for many analysts: it involves all at the same time grouping, ordering, and window functions. It also is not likely ever the analyst’s end goal but a sub-step needed to transform data on the way to the prediction, modeling, analysis, or presentation they actually wish to get back to.
Iris, by Diliff – Own work, CC BY-SA 3.0, Link
In our previous article in this series we discussed the general ideas of “row-ID independent data manipulation” and “Split-Apply-Combine”. Here, continuing with our example, we will specialize to a data analysis pattern I call: “Grouped-Ordered-Apply”. Continue reading Organize your data manipulation in terms of “grouped ordered apply”
Statisticians and data scientists want a neat world where data is arranged in a table such that every row is an observation or instance, and every column is a variable or measurement. Getting to this state of “ready to model format” (often called a denormalized form by relational algebra types) often requires quite a bit of data manipulation. This is how
data.frames describe themselves (try “
str(data.frame(x=1:2))” in an
R-console to see this) and is part of the tidy data manifesto.
SQL (structured query language) and
dplyr can make the data arrangement process less burdensome, but using them effectively requires “index free thinking” where the data are not thought of in terms of row indices. We will explain and motivate this idea below. Continue reading The case for index-free data manipulation