You want to recode a continuous variable to another variable.

For the examples here, we’ll use a subset of the PlantGrowth data set.

# Work on a subset of the PlantGrowth data set
pg <- PlantGrowth[c(1,2,11,21,22), ]
pg

weight group
  4.17  ctrl
  5.58  ctrl
  4.81  trt1
  6.31  trt2
  5.12  trt2

In this example, we’ll recode the continuous variable weight into a categorical variable, wtclass, using the cut() function:

pg$wtclass <- cut(pg$weight, breaks = c(0, 5, 6, Inf))
pg

 weight group wtclass
   4.17  ctrl   (0,5]
   5.58  ctrl   (5,6]
   4.81  trt1   (0,5]
   4.17  trt1   (0,5]
   6.31  trt2 (6,Inf]
   5.12  trt2   (5,6]