Dataframe and matrices

#creating a dataframe
employee<-data.frame(empid=c(12,15,11,13,18),empname=c("raj","ravi","prem","kishore","ajay"),salary=c(20,30,40,50,60),start_date=as.Date(c("2020-12-26","2020-12-2","2020-11-26","2020-10-3","2020-12-21")),stringsAsFactors=FALSE)
employee  
#extracting data from dataframe
employee[,1:2]
employee[c(2,5),]
employee[,c(1,3)]
employee[c(3,5),c(2,4)]
employee[2,4]
#summary of dataframe
summary(employee)
#extracting data from dataframe using columnnames
employee$salary
#matrix
m<-matrix(1:9,3,3,byrow = TRUE )
m
#assigning row name LETTERS MENTIONING ALPHABETICAL
rownames(m)<-LETTERS[1:3]
#assigning column name
colnames(m)<-LETTERS[24:26]
#transposition of matrix t()
P<-t(m)
P
#rbind and cbind
rbind(a=1:3,b=c(4,8,6),c=c(9,2,8))
cbind(a=1:3,b=c(4,8,6),c=c(9,2,8))

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