unclass Function in R (2 Examples)


In this R tutorial you’ll learn how to apply the unclass() function.

The post is structured as follows:

Let’s just jump right in…


Creating Example Data

We’ll use the following data as a basis for this tutorial:

my_fac <- factor(c("A", "B", "A", "A", "C"))    # Create example factor
my_fac                                          # Print example factor
# [1] A B A A C
# Levels: A B C

As you can see based on the previously shown output of the RStudio console, our example data is a factor vector containing the three different factor levels A, B, and C.


Example 1: Convert Factor to Integer Using unclass() Function

The following R programming syntax shows how to use the unclass function to transform a factor vector to an integer.

Consider the R code below:

my_fac_new1 <- unclass(my_fac)                  # Convert factor to integer
my_fac_new1                                     # Print output
# [1] 1 2 1 1 3
# attr(,"levels")
# [1] "A" "B" "C"

As you can see, we have created a new data object called my_fac_new1, which contains integer values that correspond to the different levels of our input factor.

Let’s check the data class of this new data object:

class(my_fac_new1)                              # Check class of updated data
# [1] "integer"

As you can see, our new data object has the integer class.


Example 2: Change Group Names of Factor Using unclass() Function

This example shows how to use the unclass command to change the groups/categories of a factor object.

For this, we first have to create a new vector that contains the new group names:

new_names <- c("gr1", "gr2", "gr3")             # Specify new group names
new_names                                       # Print new group names
# [1] "gr1" "gr2" "gr3"

Next, we can use the unclass function to switch the categories in our factor to the new names:

my_fac_new2 <- new_names[unclass(my_fac)]       # Change factor levels
my_fac_new2                                     # Print new data
# [1] "gr1" "gr2" "gr1" "gr1" "gr3"

The factor level A was renamed to “gr1”, B was renamed to “gr2”, and C was renamed to “gr3”.

Note that the previously created data object my_fac_new2 has the character class. You might convert this vector back to the factor class, though.


Video, Further Resources & Summary

Do you need further explanations on the R programming code of this article? Then you might have a look at the following video on my YouTube channel. In the video, I’m explaining the topics of this tutorial.


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In addition, you may have a look at the other tutorials on this website:


To summarize: You have learned in this tutorial how to use the unclass() function in R programming. In case you have any further questions, let me know in the comments section below.


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