R lapply()

1 개요

R lapply()

x <- c(2,3,4)
unlist(lapply(x, function(n){ n*n }))
## [1]  4  9 16
x**2
## [1]  4  9 16

x <- list(1:3, 1:4, 1:5)
x
## [[1]]
## [1] 1 2 3
## 
## [[2]]
## [1] 1 2 3 4
## 
## [[3]]
## [1] 1 2 3 4 5

lapply(x, mean)
## [[1]]
## [1] 2
## 
## [[2]]
## [1] 2.5
## 
## [[3]]
## [1] 3

unlist(lapply(x, mean))
## [1] 2.0 2.5 3.0

movies <- c("SPYDERMAN","BATMAN","VERTIGO","CHINATOWN")
unlist(lapply(movies, tolower))
## [1] "spyderman" "batman"    "vertigo"   "chinatown"
unlist(lapply(movies, nchar))
## [1] 9 6 7 9

2 같이 보기

• R sapply()
• R apply 패밀리
• 함수 map()

3 참고

• https://www.rdocumentation.org/packages/base/versions/3.6.0/topics/lapply