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Teaching pivot / un-pivot

Authors: John Mount and Nina Zumel Introduction In teaching thinking in terms of coordinatized data we find the hardest operations to teach are joins and pivot. One thing we commented on is that moving data values into columns, or into a “thin” or entity/attribute/value form (often called “un-pivoting”, “stacking”, “melting” […]

Visualizing relational joins

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 […]

Coordinatized Data: A Fluid Data Specification

Authors: John Mount and Nina Zumel. Introduction It has been our experience when teaching the data wrangling part of data science that students often have difficulty understanding the conversion to and from row-oriented and column-oriented data formats (what is commonly called pivoting and un-pivoting). Boris Artzybasheff illustration Real trust and […]

On Writing Our Book: A Little Philosophy

We recently got this question from a subscriber to our book: … will you in any way describe what subject areas, backgrounds, courses etc. would help a non data scientist prepare themselves to at least understand at a deeper level why they techniques you will discuss work…and also understand the […]