RStudio Trainer Program

Tidyverse: Split-Apply-Combine Strategy - Assessment

Tidyverse Korea

1 Multiple Choice Question

Split-Apply-Combine strategy is an attractive conceptual model in terms of removing for loops. from the following R workflow, which is the Split-Apply-Combine strategy?

1. split → lapply → do.call
2. ddplyr: .data, .variable, .fun
3. tidyverse: group_by, do
4. split → map_dfr
5. group_by → nest() → mutate(map())
6. All of them

Hint: R 병렬 프로그래밍 - “분할-적용-병합(Split-Apply-Combine) 전략”

2 Parsons Problems

Instruction

• Use iris_tbl dataframe
• Group by Species, and then nest()

• Calculate Sepal.Length mean through mutate(), map() pattern

Write Code

iris_tbl %>% 
  ____(Species) %>% 
  nest() %>% 
  ____(mean_sepal_length = map____(data, ~mean(.$`_____`)))