[R] Using diff and transform

[eric]

I want to use diff to take the differences in a column "Close" of a data
frame "y". But I'd like to do it using the transform function so a new data
frame is created with a difference column. The problem is that diff gives
one less than the number of elements in the original data frame. So
transform gives an error message. I know the first element of diff should be
NA or ideally 0. But not sure how I get there. Any suggestions ?


j
        Date   Close
1 11/20/1985 156.412
2 11/21/1985 155.112
3 11/22/1985 154.182
4 11/25/1985 154.192
5 11/26/1985 153.722
6 11/27/1985 153.712

d <-diff(j[,2])
d
[1] -1.30 -0.93  0.01 -0.47 -0.01

j <- transform(j, delta=diff(j[,2]))

Error in data.frame(list(Date = c(5620L, 5639L, 5657L, 5706L, 5721L, 5736L : 
  arguments imply differing number of rows: 6, 5
Calls: transform -> transform.data.frame -> do.call -> data.frame

-- 
View this message in context: http://r.789695.n4.nabble.com/Using-diff-and-transform-tp3237397p3237397.html
Sent from the R help mailing list archive at Nabble.com.