[R] diff doesnot work

William Dunlap wdunlap at tibco.com
Mon Feb 6 23:28:25 CET 2017


diff() does not work on data.frames so you need to give it a column
from the data.frame, as a vector.
  diff(data.frame(P=c(1,2,3,5,7,11,13,17))$P)
  [1] 1 1 2 2 4 2 4

You get different errors for multi- and single-column data.frames
  > diff(data.frame(P=c(1,2,3,5,7,11,13,17), F=c(1,1,2,3,5,8,13,21)))
  Error in r[i1] - r[-length(r):-(length(r) - lag + 1L)] :
    non-numeric argument to binary operator
  > diff(data.frame(P=c(1,2,3,5,7,11,13,17)))
  data frame with 0 columns and 8 rows
Bill Dunlap
TIBCO Software
wdunlap tibco.com


On Mon, Feb 6, 2017 at 2:21 PM, george brida <george.brida at gmail.com> wrote:
> Dear R users,
>
> I have a txt file entitled coc composed by one column of numeric values
> without header and having 50 rows. This file is under the following path:
>
> C:\\Users\\intel\\Documents\\TR
>
> I have written the following lines:
>
> xcx=read.table("C:\\Users\\intel\\Documents\\TR\\coc.txt",header=F)
> xc=log(xcx)
>
> I have obtained the series xc but when I wrote
> x=diff(xc)
>
> I obtained the following message:
>
> data frame with 0 columns and 50 rows
>
> I don't know where is the problem. Can you help me please
>
>         [[alternative HTML version deleted]]
>
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