[R] re ferring to data of previous rows

[Gabor Grothendieck]

Iff dd is your data frame then:

dd$prev <- ave(dd$of, dd$Id, FUN = function(x) c(NA, head(x, -1)))


On Wed, Oct 21, 2009 at 2:55 AM, clion <birte_2 at hotmail.com> wrote:
>
> Dear Rlers,
> in the following dataset I would like to insert a new column that refers to
> the data of the previous row.
> My question is whether the probability of a female (Id) changes if she had
> given birth to a pup in the previous year. So my dataframe consists of the
> column Id, year (2003-2007 for each Id) and offspring (=of; 1-0):
> Id   year   of
> 1   2003   1
> 1   2004   0
> 1   2005   1
> 1   2006   1
> 1   2007   0      with 1= female (Id) gave birth to offspring (same year)
> 2   2003   0      and 0 = female didn't pup
> 2   2004   1
> 2   2005   1
> 2   2006   0
> 2   2007   1
> 3   2003   1
> 3   2004   1
> 3   2005   1
> 3   2006   0
> 3   2007   0
> Now I want to add the column "offspring in the previous year - yes/no(1-0)"
> the output now should look like this:
>
> Id  year   of   of_inPreviousYear
> 1   2003   1   NA
> 1   2004   0   1
> 1   2005   1   0
> 1   2006   1   1
> 1   2007   0   1
> 2   2003   0   NA
> 2   2004   1   0
> 2   2005   1   1
> 2   2006   0   1
> 2   2007   1   0
> 3   2003   1   NA
> 3   2004   1   1
> 3   2005   1   1
> 3   2006   0   1
> 3   2007   0   0
>
> any idea how I could program that?
>
> thanks a lot,
> clion
> --
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