Check if an Element is present in an R Vector

Vectors are a commonly used data structure in R. They are used to store sequential (and one-dimensional) values of the same type. In this tutorial, we will look at how to check if an element is present in an R vector with the help of some examples.

How to check if a vector contains an element in R?

You can use the %in% operator in R to check if an element is present in a vector or not. The following is the syntax –

# check if element e is present in vector vec
e %in% vec

It returns TRUE if the value is present in the vector and FALSE if it’s not.

Examples

Let’s look at some examples of using the above syntax to check if a vector contains a given element or not. First, we will create a vector that we will be using throughout this tutorial.

# create a vector
vec <- c(2, 4, 6, 8, 10)
# display the vector
print(vec)

Output:

[1]  2  4  6  8 10

We have a vector of even numbers from 2 to 10.

Using %in% to check if an element is present in a vector

Let’s check if the element 4 is present in the above vector.

# check if 4 is present in vec
4 %in% vec

Output:

TRUE

We get TRUE as the output since the element 4 is present in the vector, vec.

Let’s look at another example, this time we’ll check with a value that is not present in the above vector. For example, 5.

# check if 5 is present in vec
5 %in% vec

Output:

FALSE

We get FALSE as the output as the element 5 is not present in the above vector.

Using is.element() to check if an element is present in a vector

Alternatively, you can also use the is.element() function in R to check if an element is present in a vector or not. For this, pass the element as the first argument and the vector as the second argument.

Let’s use the same example as above. We’ll check whether the element 4 is present in the vector vec or not.

# check if 4 is present in vec
is.element(4, vec)

Output:

TRUE

We get the same result as above.

You might also be interested in –

• Create a Vector in R – With Examples
• R – Get Element by Index in a Vector
• How to Print a Vector in R?
• R – Get the Length of a Vector