Vectors are a common data structure in R. We generally use vectors to store a sequence of values of the same type. In this tutorial, we will look at how to get an element by its index in a vector in R with the help of some examples.
How to get an element by index in a vector?
Elements in a vector are indexed starting from 1. Use the
 notation to get a vector element by its index in R. The following is the syntax –
# get element at index i in a vector vec[i]
It returns the element present in the vector at the ith index.
Let’s look at some examples of extracting elements using their respective index in R. First, we will create a vector that we will be using throughout this tutorial.
# create a vector vec <- c(10, 20, 30, 40, 50) # display the vector print(vec)
 10 20 30 40 50
Get the value at an index in a vector
Let’s use the above syntax to get the value at the index 2 in the
# get element in vector at index 2 print(vec)
20 as the output, which is the value at the second index in the vector,
vec. Let’s now look at some more specific use-cases.
Get the first element in a vector
Let’s get the first value in the above vector. We know that a vector is indexed starting from 1 in R. So, the first value is present at index 1. Let’s use the above syntax to get the first value.
# get the first element in the vector print(vec)
We get the first value in the above vector as
Get the last element in a vector
You can similarly get the last value in a vector. The last value will present at the index which is equal to the length of the vector. You can use the
length() function in R to get the length of a vector.
# get the last element in the vector print(vec[length(vec)])
Here, we first use the
length() function to find the length of the vector (which is the same as the index of the last element) and then use the
 notation to get the value at that index. We get
50 as the last element in the above vector.
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