R case_when()

1 개요

R case_when()

• "A General Vectorised If → 범용 벡터화된 If"
• SQL CASE WHEN 문과 유사하다.

library(dplyr, quietly=T)
x <- 1:50
case_when(
  x %% 35 == 0 ~ "fizz buzz",
  x %% 5 == 0 ~ "fizz",
  x %% 7 == 0 ~ "buzz",
  TRUE ~ as.character(x)
)

library(dplyr, quietly=T)
x <- 1:50
case_when(
  TRUE ~ as.character(x),
  x %%  5 == 0 ~ "fizz",
  x %%  7 == 0 ~ "buzz",
  x %% 35 == 0 ~ "fizz buzz"
)

library(dplyr, quietly=T)
x <- 1:50
case_when(
  x %% 35 == 0 ~ NA_character_,
  x %% 5 == 0 ~ "fizz",
  x %% 7 == 0 ~ "buzz",
  TRUE ~ as.character(x)
)

library(dplyr, quietly=T)
x <- 1:50
case_when(
  x %% 35 == 0 ~ 35,
  x %% 5 == 0 ~ 5,
  x %% 7 == 0 ~ 7,
  TRUE ~ NA_real_
)

library(dplyr, quietly=T)
x <- 1:50
case_when(
  x %% 35 == 0 ~ 35,
  x %% 5 == 0 ~ 5,
  x %% 7 == 0 ~ 7,
  TRUE ~ NA
)

library(dplyr, quietly=T)
starwars %>%
  select(name:mass, gender, species) %>%
  mutate(
    type = case_when(
      height > 200 | mass > 200 ~ "large",
      species == "Droid"        ~ "robot",
      TRUE                      ~  "other"
    )
  )

library(dplyr, quietly=T)
x <- 1:50
patterns <- list(
  x %% 35 == 0 ~ "fizz buzz",
  x %% 5 == 0 ~ "fizz",
  x %% 7 == 0 ~ "buzz",
  TRUE ~ as.character(x)
)
case_when(!!!patterns)

2 같이 보기

• SQL CASE WHEN

3 참고

• https://www.rdocumentation.org/packages/dplyr/versions/0.7.8/topics/case_when