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Clean up your data with keep

Since the beginning of this course, we have been using the results of a weeklong A/B test.

We have put these results in a list called all_visits. This list contains visit_a, visit_b, and visit_c. These vectors are unnamed. They all contain seven numbers, one for each day of the week.

The first question we want to ask is: which days reached more than 100 visits an hour on average? We will use the keep() function. But the answer would not be readable with an unnamed vector: you would have the numbers, but you would not know to which day these numbers correspond.

The good news is: you can use the set_names() function to solve this issue. This is what we'll do in this chapter: first, use keep() on unnamed vectors, then on named ones.

This exercise is part of the course

Intermediate Functional Programming with purrr

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Exercise instructions

  • Create a mapper that will test if .x is more than 100. You'll use it twice.
  • Combining this mapper with keep(), and map it on the unnamed list all_visit. As the result is unnamed, you don't know which days you have kept.
  • Name each vector by combining map() and the set_names() functions, using the vector of names we have provided.
  • Map the previously created mapper on the newly named list. As you can see, it's more readable now!

Hands-on interactive exercise

Have a go at this exercise by completing this sample code.

# Create a mapper that test if .x is more than 100 
is_more_than_hundred <- ___(~ .x > 100)

# Use this mapper with keep() on the all_visits object 
map(all_visits, ~ ___(.x, is_more_than_hundred))

# Use the  day vector to set names to all_list
day <- c("mon", "tue", "wed", "thu", "fri", "sat", "sun")
full_visits_named <- map(all_visits, ~ ___(.x, ___))

# Use this mapper with keep() 
map(full_visits_named, ~ ___(.x, ___))
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