x<- "987654321"

substr(x,3,4)

a<-"1234567890"

substr(a,3,5)

r<-"RUSHALI"

substr(r,1,5)

p<-c("goodgirl", "badgirl", "goodboy", "badboy")

pattern<-"good"

print(grep(pattern,p))

pattern<-"bad"

print (grep (pattern,p))
st1 <- "MATHS is difficult to study"
sub("difficult", "easy", st1)

paste(x,a,r,sep=" ")
paste(p, st1,sep=" ")

strsplit(st1," ")
tolower(r)

toupper(r)

A<-c(1:20)

A

mean (A)
median (A)

max(A)

min(A)

range(A)

sd (A)

sum(A)

quantile (A,0.2)

diff(A,lag=3)
scale(A)