Is there an R function which converts categorical variables into continuous variables?

Question

My dataframe is of the following form:

Index: Number of pets owned: Age range

1. 10: 30s

2. 2: 50s

3. 4: 60s

4. 6: <20s

5. 9: 70s

etc. Essentially, the number of age ranges are <20s, 20s, 30s, 40s, 50s, 60s, 70s. What I would like to do is turn this categorical age range variable into a continuous one by assigning 1, 2, 3, 4, 5, 6, 7 to the age ranges. Any idea how I can do this in R? I think the as.numeric function could be useful but I've never used it before.

Answer 1

You can do that using as.numeric() function. Using your dataframe we have:

data_frame <- data.frame(
pets_owned = c("10", "2", "4","6","9"),
age_rank = c("30", "50", "60","20","70")
)

This is your Dataframe looks like:

> data_frame
  pets_owned age_rank
1         10       30
2          2       50
3          4       60
4          6       20
5          9       70

Checking the class data type of age_rank column we have:

> class(data_frame$age_rank)
[1] "factor"

So using as.numeric() :

data_frame[2]=as.numeric(data_frame$age_rank)
# update the value in the position [2] of the dataframe

This is your dataframe with the values 1, 2, 3, 4, 5 in the age rank.

> data_frame
  pets_owned age_rank
1         10        2
2          2        3
3          4        4
4          6        1 # note that the value 1 
5          9        5 # correspond with the age of 20.

Checking the column again:

> class(data_frame$age_rank)
[1] "numeric"