Create ordered level factors in R

Create ordered level factors in R, will demonstrate how to use R’s ordered() function to produce ordered factors.

Example 1: Ordered Factor from Vector Using the function ordered()

We’ll demonstrate how to convert a factor vector into an ordered factor in this example.

To begin, we must first construct an example factor vector in R:

myfac <- factor(c("X", "Y", "Z", "Z", "X"),       
levels = c("Z", "Y", "X"))
myfac

[1] X Y Z Z X
Levels: Z Y X

As you can see, our factor has three-factor levels and five constituents.

Let’s verify our data object’s class:

class(myfac)                                       
[1] "factor"

Our data object is a factor at this moment.

Now that our factor has been transformed into an ordered factor, we can use the ordered function as follows:

my_fac_ordered1 <- ordered(myfac)                   
my_fac_ordered1

[1] X Y Z Z X
Levels: Z < Y < X

Already, the output differs slightly (see the angle brackets separating the levels).

Let’s examine our changed data object’s data type:

class(my_fac_ordered1)                               
[1] "ordered" "factor"

We have changed our factor vector into an ordered factor vector, as you can see.

Keep in mind that we might use the as.ordered function to achieve the same outcome.