# Column-wise operations {#sec-column-wise} ```{r} #| results: "asis" #| echo: false source("_common.R") status("drafting") ``` ## Introduction <!--# TO DO: Write introduction. --> ### Prerequisites In this chapter we'll continue using dplyr. dplyr is a member of the core tidyverse. ```{r} #| label: setup #| message: false library(tidyverse) ``` <!--# TO DO: Write chapter around across, etc. -->