R table()

1 개요

R table()

벡터

x <- c(3,1,4,1,5,2,6,5)
table(x)
## x
## 1 2 3 4 5 6 
## 2 1 1 1 2 1

table( c(3,1,4,1,5,2,6,5) )
## 
## 1 2 3 4 5 6 
## 2 1 1 1 2 1

데이터프레임$컬럼

v <- c(1, 'hello', 1, 'world', 'hello')
table(v)
## v
##     1 hello world 
##     2     2     1

scores <- read.table( header=TRUE, stringsAsFactors=FALSE, text="
Class  Name variable value
    A Alice  English    90
    A   Bob  English    80
    B  Dave  English    60
    A Alice     Math    60
    B Carol     Math    80
    B  Dave     Math    90
")
scores
##   Class  Name variable value
## 1     A Alice  English    90
## 2     A   Bob  English    80
## 3     B  Dave  English    60
## 4     A Alice     Math    60
## 5     B Carol     Math    80
## 6     B  Dave     Math    90

table( scores$variable )
## English    Math 
##       3       3 

table( scores$value )
## 60 80 90 
##  2  2  2

table()과 ddply()

library(plyr)
table(baseball[1:100,]$year)
##
## 1871 1872 1873 1874 1875 1876 1877 1878 
##    7   13   13   15   17   15   17    3
ddply(baseball[1:100,], ~year, nrow)
ddply(baseball[1:100,], 'year', nrow)
ddply(baseball[1:100,], .(year), nrow)
##   year V1
## 1 1871  7
## 2 1872 13
## 3 1873 13
## 4 1874 15
## 5 1875 17
## 6 1876 15
## 7 1877 17
## 8 1878  3

2 같이 보기

• R tabulate()
• R ftable()
• R factor()
• R xtabs()
• R margin.table()
• R prop.table()
• R addmargins()
• R summary()
• R ddply()
• 함수 array_count_values()

3 참고

• https://www.rdocumentation.org/packages/base/versions/3.5.3/topics/table