Referencing Row Number in R

Question

How do I reference the row number of an observation? For example, if you have a data.frame called \"data\" and want to create a variable data$rownumber

Answer 1

This is probably the simplest way:

data$rownumber = 1:dim(data)[1]

It's probably worth noting that if you want to select a row by its row index, you can do this with simple bracket notation

data[3,]

vs.

data[data$rownumber==3,]

So I'm not really sure what this new column accomplishes.