Many thanks Jim.

On Tue, Jul 24, 2012 at 2:25 PM, jim holtman <jholtman@gmail.com> wrote:

> Here is another way of doing it:
>
> > states <- structure(list(Date = c("24/07/2012", "25/07/2012",
> "26/07/2012",
> + "27/07/2012", "28/07/2012", "24/07/2012", "25/07/2012", "26/07/2012",
> + "27/07/2012", "28/07/2012"), State = c(1L, 1L, 1L, 1L, 1L, -1L,
> + -1L, -1L, 1L, -1L)), .Names = c("Date", "State"), class = "data.frame",
> + row.names = c(NA,
> + -10L))
> > # mark the state changes
> > states$diff <- c(TRUE, diff(states$State) != 0)
> > states[states$diff,]
>          Date State diff
> 1  24/07/2012     1 TRUE
> 6  24/07/2012    -1 TRUE
> 9  27/07/2012     1 TRUE
> 10 28/07/2012    -1 TRUE
>
>
> On Tue, Jul 24, 2012 at 2:40 AM, Raghuraman Ramachandran
> <optionsraghu@gmail.com> wrote:
> > Hello
> >
> > I have a data frame like this:
> > dput(states)
> > structure(list(Date = c("24/07/2012", "25/07/2012", "26/07/2012",
> > "27/07/2012", "28/07/2012", "24/07/2012", "25/07/2012", "26/07/2012",
> > "27/07/2012", "28/07/2012"), State = c(1L, 1L, 1L, 1L, 1L, -1L,
> > -1L, -1L, 1L, -1L)), .Names = c("Date", "State"), class = "data.frame",
> > row.names = c(NA,
> > -10L))
> >
> >> State
> >
> >       Date State
> > 1  24/07/2012     1
> > 2  25/07/2012     1
> > 3  26/07/2012     1
> > 4  27/07/2012     1
> > 5  28/07/2012     1
> > 6  24/07/2012    -1
> > 7  25/07/2012    -1
> > 8  26/07/2012    -1
> > 9  27/07/2012     1
> > 10 28/07/2012    -1
> >
> > I wish to collapse it into a smaller one based on the state value. If
> state
> > is 1 already then the second state (and the row) is to be removed till a
> > new state is found and so on.. States can be 1 or -1 only. So in the
> > previous example the new data frame should be:
> >
> >   Date State  24/07/2012 1  24/07/2012 -1  27/07/2012 1  28/07/2012 -1
>  Can
> > someone help?
> >
> > Thx
> > Raghu
> >
> >         [[alternative HTML version deleted]]
> >
> > ______________________________________________
> > R-help@r-project.org mailing list
> > https://stat.ethz.ch/mailman/listinfo/r-help
> > PLEASE do read the posting guide
> http://www.R-project.org/posting-guide.html
> > and provide commented, minimal, self-contained, reproducible code.
>
>
>
> --
> Jim Holtman
> Data Munger Guru
>
> What is the problem that you are trying to solve?
> Tell me what you want to do, not how you want to do it.
>

	[[alternative HTML version deleted]]

