Online Test Banks
Score higher
See Online Test Banks
Learning anything is easy
Browse Online Courses
Mobile Apps
Learning on the go
Explore Mobile Apps
Dummies Store
Shop for books and more
Start Shopping

How to Store and Calculate Values in R

Using R as a calculator is very interesting but perhaps not all that useful. A much more useful capability is storing values and then doing calculations on these stored values.

Try the following:

> x <- 1:5
> x
[1] 1 2 3 4 5

In these two lines of code, you first assign the sequence 1:5 to a variable called x. Then you ask R to print the value of x by typing x in the console and pressing Enter.

In R, the assignment operator is <-, which you type in the console by using two keystrokes: the less-than symbol (<) followed by a hyphen (-). The combination of these two symbols represents assignment.

In addition to retrieving the value of a variable, you can do calculations on that value. Create a second variable called y, and assign it the value 10. Then add the values of x and y, as follows:

> y <- 10
> x + y
[1] 11 12 13 14 15

The values of the two variables themselves don’t change unless you assign a new value. You can check this by typing the following:

> x
[1] 1 2 3 4 5
> y
[1] 10

Now create a new variable z, assign it the value of x+y, and print its value:

> z <- x + y
> z
[1] 11 12 13 14 15

Variables also can take on text values. You can assign the value "Hello" to a variable called h, for example, by presenting the text to R inside quotation marks, like this:

> h <- "Hello"
> h
[1] "Hello"

You must present text or character values to R inside quotation marks — either single or double. R accepts both. So both h <- "Hello" and h <- 'Hello' are examples of valid R syntax.

In “Using vectors,” you use the c() function to combine numeric values into vectors. This technique also works for text. Try it:

> hw <- c("Hello", "world!")
> hw
[1] "Hello" "world!"

You can use the paste() function to concatenate multiple text elements. By default, paste() puts a space between the different elements, like this:

> paste("Hello", "world!")
[1] "Hello world!"
  • Add a Comment
  • Print
  • Share
blog comments powered by Disqus

Inside Sweepstakes

Win $500. Easy.