R help - Apr 2012 - Compare by row and insert previous row value (Or non Time Series Lag)

I have the following sample dataset (CSV input here:http://goo.gl/YR8LP.
CSV output here: http://goo.gl/EFCC8) which I want to transform as follows.
For each person in a household I want to create two new variables OrigTAZ
and DestTAZ. It should take the value in TripendTAZ and put that in
DestTAZ. For OrigTAZ it should put value of TripendTAZ from the previous
row. For the first trip of every person in a household (Tripid = 1) the
OrigTAZ = hometaz. For each person in a household, from the second trip
OrigTAZ = TripendTAZ_(n-1) (the value of TripendTAZ from the previous row)
and DestTAZ = TripEndTAZ. The sample input and output data are shown in the
links above. I tried the suggestions shown here: Basic lag in R
vector/dataframe<http://stackoverflow.com/questions/3558988/basic-lag-in-r-vector-dataframe>
but
have not had luck.

TIA,
Krishnan
-- 
Krishnan Viswanathan
1101 High Meadow Dr
Tallahassee FL 32311

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Hello my old friend. Remember me from Cambridge.

Here is the dirty way of getting your desired output and enjoy hassling
with trips that are incomplete or missing information

inpfil <- read.csv("sample_trip_od_input.csv")
aa <- split(inpfil, paste(inpfil[,1],inpfil[,2],sep=','))
OrigTAZ <- inpfil[,5]
DestTAZ <- OrigTAZ
cx <- cbind(OrigTAZ, DestTAZ)
out.data.fr <- cbind(inpfil[FALSE,], cx[FALSE,])
for( i in 1:length(aa)) {
 bb <- as.data.frame(aa[i])
 for( j in 1:5) {names(bb)[j] <- names(inpfil)[j]}
 bb.len <- length(bb)
 OrigTAZ <- bb[1:(bb.len-1),5]
 DestTAZ <- bb[2:bb.len,5]
 cc <- cbind(OrigTAZ, DestTAZ)
 cc.fill <- cbind(bb[1,4],cc[1,1])
 cc <- rbind(cc.fill, cc)
 bb  <- cbind(bb,cc)
 out.data.fr <- rbind(out.data.fr,bb)
}
out.data.fr

AA
+1 (617) 595-1068

On Tue, Apr 3, 2012 at 5:30 AM, Krishnan Viswanathan <
krisviswanathan@gmail.com> wrote:
> I have the following sample dataset (CSV input here:http://goo.gl/YR8LP.
> CSV output here: http://goo.gl/EFCC8) which I want to transform as
> follows.
> For each person in a household I want to create two new variables OrigTAZ
> and DestTAZ. It should take the value in TripendTAZ and put that in
> DestTAZ. For OrigTAZ it should put value of TripendTAZ from the previous
> row. For the first trip of every person in a household (Tripid = 1) the
> OrigTAZ = hometaz. For each person in a household, from the second trip
> OrigTAZ = TripendTAZ_(n-1) (the value of TripendTAZ from the previous row)
> and DestTAZ = TripEndTAZ. The sample input and output data are shown in the
> links above. I tried the suggestions shown here: Basic lag in R
> vector/dataframe<
> http://stackoverflow.com/questions/3558988/basic-lag-in-r-vector-dataframe
> >
> but
> have not had luck.
>
> TIA,
> Krishnan
> --
> Krishnan Viswanathan
> 1101 High Meadow Dr
> Tallahassee FL 32311
>
>
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