Solving iteration problems with purrr

Keywords: purrr, tidyverse, tibble

Outline

Code with a lot of duplication is harder to understand, troubleshoot and maintain. The goal of this tutorial is help you remove duplication in your code by using functions that write for loops for you.

You’ll learn to use the functions in the purrr package to perform iterative tasks: tasks that look like “for each _____ do _____”.

By the end of the tutorial you’ll be writing code that is more readable and easier to update and you’ll be ready to solve new iteration problems faster and with fewer mistakes.

Learning Objectives

By the end of the tutorial, you’ll be able to:

• Move from solving a problem on a single element, to iterating that solution over many elements with map().
• Identify when to use the typed variants of map(): map_lgl(), map_int(), walk() etc.
• Iterate over two arguments with map2().
• Leverage purrr to get list data into tibbles.
• Use purrr to work with list columns in tibbles.

Pre-requisites

Don’t worry if you have never written a for loop, used lapply(), written your own function or heard of a tibble, this tutorial is designed to be accessible to beginners.

That said, you should be familiar with exploring and subsetting the basic data structures in R including lists and data frames.

This is a hands-on tutorial, you’ll need your laptop with R and purrr installed. Check http://bit.ly/purrr-user17 closer to the date for more details.

Instructor Info

Charlotte Wickham

• cwickham@gmail.com
• cwick.co.nz
• @cvwickham