## Mapping leaves

Recursive functional programming

I love purrr.1 Aside from its anonymous function notation, one of the functions that made me love the package was at_depth, which iterates across a list at a specified level of nesting. It has since been deprecated in favor of modify_depth, which is more powerful, but is significantly more finicky.

## Fireworks

Animating fireworks with ggplot2 and gganimate

When aggregating data, it is not uncommon to need to combine datasets containing identical non-key variables in varying states of completeness. There are various ways to accomplish this task. One possibility an coalescing join, a join in which missing values in x are filled with matching values from y. Such behavior does not exist in current dplyr joins, though it has been discussed, and so may someday. For now, let’s build an coalesce_join function.