How do I name the "row names" column in r

Question

I'm working with a data frame in r where my row names are meaningful. Hence, I would like to give the column of row names a name. How do I do this?

Answer 1

It sounds like you want to convert the rownames to a proper column of the data.frame. eg:

# add the rownames as a proper column myDF <- cbind(Row.Names = rownames(myDF), myDF) myDF  #           Row.Names id val vr2 # row_one     row_one  A   1  23 # row_two     row_two  A   2  24 # row_three row_three  B   3  25 # row_four   row_four  C   4  26 

If you want to then remove the original rownames:

rownames(myDF) <- NULL myDF #   Row.Names id val vr2 # 1   row_one  A   1  23 # 2   row_two  A   2  24 # 3 row_three  B   3  25 # 4  row_four  C   4  26 

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Alternatively, if all of your data is of the same class (ie, all numeric, or all string), you can convert to Matrix and name the dimnames

myMat <- as.matrix(myDF) names(dimnames(myMat)) <- c("Names.of.Rows", "") myMat  # Names.of.Rows id  val vr2  #   row_one   "A" "1" "23" #   row_two   "A" "2" "24" #   row_three "B" "3" "25" #   row_four  "C" "4" "26" 

Answer 2

The tibble package now has a dedicated function that converts row names to an explicit variable.

library(tibble) rownames_to_column(mtcars, var="das_Auto") %>% head 

Gives:

           das_Auto  mpg cyl disp  hp drat    wt  qsec vs am gear carb 1         Mazda RX4 21.0   6  160 110 3.90 2.620 16.46  0  1    4    4 2     Mazda RX4 Wag 21.0   6  160 110 3.90 2.875 17.02  0  1    4    4 3        Datsun 710 22.8   4  108  93 3.85 2.320 18.61  1  1    4    1 4    Hornet 4 Drive 21.4   6  258 110 3.08 3.215 19.44  1  0    3    1 5 Hornet Sportabout 18.7   8  360 175 3.15 3.440 17.02  0  0    3    2 6           Valiant 18.1   6  225 105 2.76 3.460 20.22  1  0    3    1