https://medium.com/@keith.mcnulty/utilizing-quosures-to-create-ultra-flexible-filtering-controls-in-r-shiny-f3e5dc461399

I build R Shiny apps quite a lot, and one of the common uses is to allow dynamic filtering of the underlying data, so that you can adjust a chart or a table based on some particular subset of interest.

Normally, we hardcode the filtering options into a sidebar menu of some form, and define input picklists for the fields of interest. For example, if we were filtering the mtcars dataset, we might offer an input picklist like this on the UI side: