In the previous set we started with arithmetic operations on vectors. We’ll take this a step further now, by practising functions to summarize, sort and round the elements of a vector. Sofar, the functions we have practised (log, sqrt, exp, sin, cos, and acos) always return a vector with the same length as the input […]
vectors and sequences
Working With Vectors
In the previous exercise set we practised vectors as a data structure. As I noted at the beginning of that set, perhaps you were already familiar with data in a vector-like structure in other applications such as Microsoft Excel or SPSS. If so, perhaps you also used those data to carry out calculations. In this […]
Creating vectors
A vector is the most elementary way to store and structure data in R. For now, think of it as a list of numbers, which can be as short as a single number, or as long as about 2 billion(!) numbers. Perhaps you were used to working with lists of numbers already in a spreadsheet […]
Protected: Comparing Vectors Exercises
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How to create your first vector in R
Are you an expert R programmer? If so, this is *not* for you. This is a short tutorial for R novices, explaining vectors, a basic R data structure. Here’s an example: 10 150 30 45 20.3 And here’s another one: -5 -4 -3 -2 -1 0 1 2 3 still another one: “Darth Vader” “Luke […]
Vectors Vol. 2 Exercises
[For this exercise, first write down your answer, without using R. Then, check your answer using R.] Answers to the exercises are available here. Exercise 1 Consider two vectors, x, y x=c(4,6,5,7,10,9,4,15) y=c(0,10,1,8,2,3,4,1) What is the value of: x*y Exercise 2 Consider two vectors, a, b a=c(1,2,4,5,6) b=c(3,2,4,1,9) What is the value of: cbind(a,b) Exercise […]
Regular Sequences Vol. 2 Exercises
[For this exercise, first write down your answer, without using R. Then, check your answer using R.] Answers to the exercises are available here. Exercise 1 if x <- c(a = 1, b = 2,c=3,d=4) What is the output for the code: seq(5,11,along.with =x) Exercise 2 If x= seq(4,12,4) , what is the output for […]
Index vectors
In the exercises below we cover the basics of index vectors. Before proceeding, first read section 2.7 of An Introduction to R, and the help pages for the sum, and which functions. Answers to the exercises are available here. Exercise 1 If x Are you a beginner (1 star), intermediate (2 stars) or advanced (3 […]
Character vector exercises
In the exercises below we cover the basics of character vectors. Before proceeding, first read section 2.6 of An Introduction to R, and the help pages for the nchar, substr and sub functions. Answers to the exercises are available here. Exercise 1 If x Are you a beginner (1 star), intermediate (2 stars) or advanced […]
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?