How to create your first vector in R
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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 Skywalker" "Han Solo"
and our final example:
389.3491
These examples show that a vector is, simply speaking, just a collection of one (fourth example) or more (first and second example) numbers or character strings (third example). In R, a vector is considered a data structure (it’s a very simple data structure, and we’ll cover more complex structures in another tutorial).
So, how can we set up and use a vector in R?
We can construct a vector from a series of individual elements, using the c()
function, as follows:
c(10, 150, 30, 45, 20.3)
## [1] 10.0 150.0 30.0 45.0 20.3
(In examples like these, lines starting with ##
show the output from R on the screen).
Assigning a vector
As you’ll see, once you have entered the vector, R will respond by displaying its elements. In many cases it will be convenient to refer to this vector using a name, instead of having to enter it over and over again. We can accomplish this using the assign()
function, which is equivalent to the <-
and =
operators:
assign('a', c(10, 150, 30, 45, 20.3)) a <- c(10, 150, 30, 45, 20.3) a = c(10, 150, 30, 45, 20.3)
The second statement (using the <-
operator) is the most common way of assigning in R, and we’ll therefore use this form rather than the =
operator or the assign()
function.
Once we have assigned a vector to a name, we can refer to the vector using this name. For example, if we type a, R will now show the elements of vector a.
a
## [1] 10.0 150.0 30.0 45.0 20.3
Instead of a, we could have chosen any other name, e.g.:
aVeryLongNameWhichIsCaseSensitive_AndDoesNotContainSpaces <- c(10, 150, 30, 45, 20.3)
Strictly speaking, we call this “name” an object.
To familiarize yourself with the vector data structure, now try to construct a couple of vectors in R and assign them to a named object, as in the example above.
To summarize: A vector is a data structure, which can be constructed using the c()
function, and assigned to a named object using the <-
operator.
Now, let’s move on to the first set of real exercises on vectors!
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