Below are the solutions to these exercises on missing values. # Exercise 1 # Answer: 6 # Exercise 2 # Answer: a # Exercise 3 # Answer: b # Exercise 4 # Answer: C # Exercise 5 W <- c (11, 3, 5, NA, 6) is.na(W) ## [1] FALSE FALSE FALSE TRUE FALSE # Exercise […]

## Missing values

Today we’re training how to handle missing values in a data set. Before starting the exercises, please first read section 2.5 of An Introduction to R. Solutions are available here. Exercise 1 If X Are you a beginner (1 star), intermediate (2 stars) or advanced (3 stars) R user?

## Matrix exercises: solutions

Below are the solutions to these matrix exercises. #1. x<-c(1,2,3) y<-c(4,5,6) z<-c(7,8,9) A<-cbind(x,y,z) rownames(A)<-c(“a”,”b”,”c”) ####if combined by rows A<-rbind(x,y,z) #2. is.matrix(A) ## [1] TRUE #if A is a data.frame then this should return false. So please note the #different usages between data.frame and matrix. #3. b<-c(1:12) B<-matrix(b, 4, 3, dimnames = list(c(“a”,”b”,”c”,”d”),c(“x”, “y”, “z”))) #4. […]

## Logical vectors and operators: solutions

Below are the solutions to these exercises on logical vectors and operators. # Solutions data <- mtcars # Q1 data[data$mpg > 15 & data$mpg < 20,] ## mpg cyl disp hp drat wt qsec vs am gear carb ## Hornet Sportabout 18.7 8 360.0 175 3.15 3.440 17.02 0 0 3 2 ## Valiant 18.1 […]

## Array exercises

Exercise 1 Create an array (3 dimensional) of 24 elements using the dim() function. Exercise 2 Create an array (3 dimensional) of 24 elements using the array() function. Exercise 3 Assign some dimnames of your choice to the array using the dimnames() function. Exercise 4 Assign some dimnames of your choice to the array using […]

## Matrix exercises

Please note, solutions are available here. Exercise 1 Create three vectors x,y,z with integers and each vector has 3 elements. Combine the three vectors to become a 3×3 matrix A where each column represents a vector. Change the row names to a,b,c. Think: How about each row represents a vector, can you modify your code […]

## Logical vectors and operators

Before you start, enter the following code: data How difficult was this for you? (1 star=easy, 10 stars=hard) Are you a beginner (1 star), intermediate (2 stars) or advanced (3 stars) R user?

## Regular sequences: solutions

Below are the solutions to these regular sequence exercises. # Excercise 1 # Using the seq() function generate the sequence 2,5,8,11 seq(from = 2,to = 13,by = 3) ## [1] 2 5 8 11 # Exercise 2: # Use the seq() function to generate the sequence 9,18,27,36,45 seq(from = 9, to = 45, by = […]

## Regular sequences

Before proceeding, please review Chapter 2 of An Introduction to R and the internal R Documentation for the seq() function (type ?seq in the R console). Solutions are available here. Excercise 1 Using the seq() function, generate the sequence 2, 5, 8, 11. Exercise 2 Use the seq() function to generate the sequence 9, […]

## Vector exercises: solutions

Below are the solutions to these vector exercises. Exercise 1 answer e Exercise 2 answer e Exercise 3 answer c Exercise 4 answer b Exercise 5 answer d Exercise 6 answer c Exercise 7 answer c Exercise 8 answer c Please help us to improve R-exercises: Did you […]