Ignore last reply. I sent the wrong script.
> set.seed(1001)
>
> # Raw data in long format --
> raw <- data.frame(name=c("f1","f1","f1","f1","f2","f2","f2","f2"),
+ year=c(83, 84, 85, 86, 83, 84, 85, 86),
+ state=sample(1:3, 8, replace=TRUE)
+ )
> # Shift to wide format --
> fixedup <- reshape(raw, timevar="year", idvar="name", v.names="state",
+ direction="wide")
>
> trans <- as.matrix(fixedup)
> result <- NULL
> # loop through all the columns and build up the 'result'
> for (i in 2:(ncol(trans) - 1)){
+ result <- rbind(result, cbind(name=trans[,1], PREV=trans[,i],
NEXT=trans[,i+1]))
+ }
> result
name PREV NEXT
1 "f1" "3" "2"
5 "f2" "2" "3"
1 "f1" "2" "2"
5 "f2" "3" "1"
1 "f1" "2" "2"
5 "f2" "1" "1"
>
> (markov <- table(result[,"PREV"], result[,"NEXT"]))
1 2 3
1 1 0 0
2 0 2 1
3 1 1 0
On 1/21/06, jim holtman <[EMAIL PROTECTED]> wrote:
>
> Is this what you want:
>
>
> set.seed(1001)
>
> # Raw data in long format --
> raw <- data.frame(name=c("f1","f1","f1","f1","f2","f2","f2","f2"),
> year=c(83, 84, 85, 86, 83, 84, 85, 86),
> state=sample(1:3, 8, replace=TRUE)
> )
> # Shift to wide format --
> fixedup <- reshape(raw, timevar="year", idvar="name", v.names="state",
> direction="wide")
>
> trans <- as.matrix(fixedup)
> result <- NULL
> for (i in 2:(ncol(trans) - 1)){
> result <- rbind(result, cbind(name=trans[,1], prev=trans[,i],
> next=trans[,i+1]))
> }
>
> result
>
> markov <- table(try$prev.state, try$new.state)
>
>
>
>
>
> On 1/21/06, Ajay Narottam Shah <[EMAIL PROTECTED]> wrote:
> >
> > Folks,
> >
> > I am holding a dataset where firms are observed for a fixed (and
> > small) set of years. The data is in "long" format - one record for one
> > firm for one point in time. A state variable is observed (a factor).
> >
> > I wish to make a markov transition matrix about the time-series
> > evolution of that state variable. The code below does this. But it's
> > hardcoded to the specific years that I observe. How might one
> > generalise this and make a general function which does this? :-)
> >
> > -ans.
> >
> >
> >
> > set.seed(1001)
> >
> > # Raw data in long format --
> > raw <- data.frame(name=c("f1","f1","f1","f1","f2","f2","f2","f2"),
> > year=c(83, 84, 85, 86, 83, 84, 85, 86),
> > state=sample(1:3, 8, replace=TRUE)
> > )
> > # Shift to wide format --
> > fixedup <- reshape(raw, timevar="year", idvar="name", v.names="state",
> > direction="wide")
> > # Now tediously build up records for an intermediate data structure
> > try <- rbind(
> > data.frame(prev=fixedup$state.83, new=fixedup$state.84),
> > data.frame(prev=fixedup$state.84, new=fixedup$state.85),
> > data.frame(prev=fixedup$state.85, new=fixedup$state.86)
> > )
> > # This is a bad method because it is hardcoded to the specific values
> > # of "year".
> > markov <- table(destination$prev.state, destination$new.state)
> >
> > --
> > Ajay Shah http://www.mayin.org/ajayshah
> >
> > [EMAIL PROTECTED]
> > http://ajayshahblog.blogspot.com
> > <*(:-? - wizard who doesn't know the answer.
> >
> > ______________________________________________
> > R-help@stat.math.ethz.ch mailing list
> > https://stat.ethz.ch/mailman/listinfo/r-help
> > PLEASE do read the posting guide!
> > http://www.R-project.org/posting-guide.html<http://www.r-project.org/posting-guide.html>
> >
>
>
>
> --
> Jim Holtman
> Cincinnati, OH
> +1 513 247 0281
>
> What the problem you are trying to solve?
--
Jim Holtman
Cincinnati, OH
+1 513 247 0281
What the problem you are trying to solve?
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