[R] add one variable to a data frame

[peter dalgaard]

Um, maybe just

dat1$C <- match(dat1$B, unique(dat1$B))

Indexing 1:k with numbers between 1 and k is a bit of a no-op...

AFAICT, this even works without stringsAsFactors=FALSE

-pd

> On 11 May 2018, at 21:30 , MacQueen, Don <macqueen1 at llnl.gov> wrote:
> 
> dat1$C <- seq(length(unique(dat1$B)))[ match( dat1$B, unique(dat1$B) )]

-- 
Peter Dalgaard, Professor,
Center for Statistics, Copenhagen Business School
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