R 기본 문법 연습 2

R 기본 문법 연습

data(iris)
head(iris)
iris3
newRow<-data.frame(Sepal.Length=3.0, Sepal.Width=3.2, Petal.Length=1.6, Petal.Width=0.3, Species= "newsetosa" )
iris<-rbind(iris,newRow)
iris
dim(iris)
newcol=1:151
iris_a<-cbind(iris,newcol)
iris_a
​
subset(iris,select=Species,subset=(Petal.Length>1.7))
subset(iris,select=c(Sepal.Length,Petal.Length,Species),subset=c(Sepal.Width==3.0 & Petal.Width==0.2))
head(with(iris,Species))
​
name<-c("Moe","Larry","Curly","Harry")
year.born<-c(1887,1902,1903,1964)
place.born<-c("BensonHurst", "Philadelphia", "Brooklyn", "Moscow")
born<-data.frame(name,year.born,place.born)
born
​
name<-c("Curly","Moe","Larry")
year.died<-c(1952,1975,1975)
died<-data.frame(name,year.died)
died
​
merge(born,died,by="name")
as.numeric("3.14")
as.integer(3.14)
as.numeric("foo")
as.character(101)
as.numeric(FALSE)
as.numeric(TRUE)
​
x<-3
as.data.frame(x)  # dataframe으로 형 변환
as.list(x)  # list로 형 변환
as.matrix(x)  #matrix로 형 변환
as.vector(x)  #vector 로 형 변환
​
paste("Everybody","loves","cats.")
paste("Everybody","loves","cats.",sep="-")
paste("Everybody","loves","cats.",sep="")
substr("BigDataAnalysis",1,4)
ss<-c("Moe","Larry","Curly")
substr(ss,1,3)
​
Sys.Date()
as.Date("2017-09-08")
as.Date("09/08/2017")
as.Date("09/08/2017",format="%m/%d/%Y")
format(Sys.Date())
as.character(Sys.Date())
format(Sys.Date(),format="%m/%d/%Y")
format(Sys.Date(),'%a')
format(Sys.Date(),'%b')
format(Sys.Date(),'%B')
format(Sys.Date(),'%d')
format(Sys.Date(),'%m')
format(Sys.Date(),'%y')
format(Sys.Date(),'%Y')
​
data(iris)
getwd()
setwd("c:/download/r_working")
write.csv(iris,file="iris.csv")
save(iris,file="iris.Rdata")
load("iris.Rdata")
read.csv("iris.csv")
​