One of the functionalities of OpenRefine that you will use most often is faceting. Facets do not affect the values of your data, but they allow you to get useful insights of your dataset; you can think of facets as various ways to look at your data, just like the facets of a gemstone that still have to be refined. Facets also allow you to apply a transformation to a subset of your data, as they allow you to display only rows corresponding to a given criterion.
In this recipe, we will explore the various ways of faceting data depending on their values and on your needs: text facets for strings, numeric facets for numbers and dates, a few predefined customized facets, and finally how to use stars and flags. Most of the power of OpenRefine lies in the ability to combine these different types of facets.