How to shift index into "recognisable format" in R?

Question

I have a dataframe that looks like this, and would like to convert the left-most column into an actual index, with the label "id".

I tried to rename it with colnames<- but it didn't work, as ncol() only returns 2. I tried to export it as a csv file, but index was similarly not captured in the file.

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Does this answer your question? [Convert row names into first column](https://stackoverflow.com/questions/29511215/convert-row-names-into-first-column) — Limey, Jan 20 '22 at 16:12

score 0 · Answer 1 · answered Jan 20 '22 at 16:14

There are a couple ways to do this. Firstly, the method you used to write to csv you can also include the row.names = TRUE parameter in the write.csv function. Otherwise, the following commands also work:

library(tibble)
df <- tibble::rownames_to_column(df, "VALUE")

(taken from Convert row names into first column)

score 0 · Answer 2 · answered Jan 20 '22 at 16:22

Example data

d <- data.frame(layer=2:4, gridpop=c(1000,2000,3000))
rownames(d) <- c("A", "B", "C")
d
#  layer gridpop
#A     2    1000
#B     3    2000
#C     4    3000

Solution

d$id <- rownames(d)
d
#  layer gridpop id
#A     2    1000  A
#B     3    2000  B
#C     4    3000  C

Or if the row names represent numbers

d$id <- as.numeric(rownames(d))

How to shift index into "recognisable format" in R?

2 Answers2