R sapply()

1 개요

R sapply()

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

movies <- c("SPYDERMAN","BATMAN","VERTIGO","CHINATOWN")
sapply(movies, tolower)
##   SPYDERMAN      BATMAN     VERTIGO   CHINATOWN 
## "spyderman"    "batman"   "vertigo" "chinatown" 
sapply(movies, nchar)
## SPYDERMAN    BATMAN   VERTIGO CHINATOWN 
##         9         6         7         9

mydf <- read.table( header=TRUE, stringsAsFactors=FALSE, text="
English Math
     90   60
     80   70
     70   80
     60   90
")
colMeans(mydf)
## English    Math 
##      75      75
sapply(mydf, mean)
## English    Math 
##      75      75

2 같이 보기

• R apply()
• R lapply()
• R colMeans()
• R apply() 패밀리
• 함수 map()

3 참고

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