15.1 Exercise 9: For loop

Create the script “exercise9.R” and save it to the “Rcourse/Module2” directory: you will save all the commands of exercise 9 in that script.
Remember you can comment the code using #.

correction

getwd()
setwd("~/Rcourse/Module2")

1- Write a for loop that iterates over 2 to 10 and prints the square root of each number (function sqrt()).

correction

for(i in 2:10){
    print(sqrt(i))
}

2- Write a for loop that iterates over 5 to 15 and prints a vector of 2 elements containing each number and its square root

correction

for(i in 5:15){
    veci <- c(i, sqrt(i))
        print(veci)
}

3- Create the following matrix

mat1 <- matrix(rnorm(40), nrow=20)

• Write a for loop that iterates over each row of mat1 and prints the median value of each row.

correction

for(j in 1:nrow(mat1)){
    # extract the row
    rowj <- mat1[j,]
    # print rowj
    print(rowj)
    # print median value in row
    print(median(rowj))
}