# [R] For and if confusion

Gabor Grothendieck ggrothendieck at gmail.com
Thu Dec 18 16:05:24 CET 2008

```Make a series of ones from each start/end pair and merge them all
with A using fill = 0.  We have returned a ts series since that seems
to be what you are using but we could have left off the as.ts to
return a zoo series in the end:

library(zoo)

X <- as.Date(c("01-03-1993", "01-05-1997"), "%d-%m-%Y")
Xs <- zoo(1, as.yearmon(seq(X[1], X[2], "month")))

Y <- as.Date(c("01-02-1995", "01-08-1999"), "%d-%m-%Y")
Ys <- zoo(1, as.yearmon(seq(Y[1], Y[2], "month")))

A <- ts(rnorm(120), freq=12, start=c(1992,8))
as.ts(with(merge.zoo(Xs, Ys, A, fill = 0), pmax(Xs, Ys)))

On Thu, Dec 18, 2008 at 5:12 AM, Shruthi Jayaram
<shruthi.jayaram.85 at gmail.com> wrote:
>
> I have two date objects
>
> X <- c("01-03-1993", "01-05-1997") #Mar 1993 and May 1997
>
> Y <- c("01-02-1995", "01-08-1999") #Feb 1995 and Aug 1999
>
> and a time series object
>
> A <- ts(rnorm(120), freq=12, start=c(1992,8)) #Aug 1992 to Aug 2002
>
> I want to create a binary (0-1) vector B that is of length 1:(A).
>
> B should have value 1 for the time periods *across* my character vectors,
> i.e. between Mar 93 ad Feb 95, and also between May-97 and Aug-99, but zero
> otherwise.
>
> Would anyone have any ideas on how to do this? I would paste the code I am
> trying, but it would confuse rather than clarify (R newbie!). Am getting
> really lost in 'for' and 'if' loops, so would really appreciate any help!
>
> Thanks!
>
> Shruthi
> --
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