Re: [R] Read 2 rows in 1 dataframe for diff - longitudinal data

2013-06-04 Thread William Dunlap
nd changes have to be detected after that year - hence we > were using ddply to group. Your solution ran very fast as expected. > > AK- I have a large dataset and your solution is taking too long - > as a matter of fact i had to kill it afte 1/2 hr on a 22K row dataset. > > Th

Re: [R] Read 2 rows in 1 dataframe for diff - longitudinal data

2013-06-04 Thread arun
Since you mentioned this > half-hour running time, it would be good to check your data.  ?str() A.K. - Original Message - From: arun To: R help Cc: David Winsemius Sent: Tuesday, June 4, 2013 1:18 PM Subject: Re: [R] Read 2 rows in 1 dataframe for diff - longitudinal data Hi, By co

Re: [R] Read 2 rows in 1 dataframe for diff - longitudinal data

2013-06-04 Thread arun
ns. -ST - Original Message - From: David Winsemius To: arun Cc: R help Sent: Tuesday, June 4, 2013 11:13 AM Subject: Re: [R] Read 2 rows in 1 dataframe for diff - longitudinal data On Jun 3, 2013, at 9:51 PM, arun wrote: > If it is grouped by "subid" (that wou

Re: [R] Read 2 rows in 1 dataframe for diff - longitudinal data

2013-06-04 Thread David Winsemius
bid, FUN=function(x) c( FALSE, x[-1] != > x[-length(x)]) ) ), ] subid year var 3 36 2003 3 7 47 2001 3 9 47 2005 1 1047 2007 3 -- David. > > > - Original Message - > From: David Winsemius > To: arun > Cc: R help > Sent: Tuesday

Re: [R] Read 2 rows in 1 dataframe for diff - longitudinal data

2013-06-04 Thread David Winsemius
s > To: arun > Cc: R help > Sent: Tuesday, June 4, 2013 12:37 AM > Subject: Re: [R] Read 2 rows in 1 dataframe for diff - longitudinal data > > > On Jun 3, 2013, at 7:10 PM, arun wrote: > >> Hi, >> May be this helps: >> res1<-df1[with(df1,unl

Re: [R] Read 2 rows in 1 dataframe for diff - longitudinal data

2013-06-03 Thread arun
al Message - From: David Winsemius To: arun Cc: R help Sent: Tuesday, June 4, 2013 12:37 AM Subject: Re: [R] Read 2 rows in 1 dataframe for diff - longitudinal data On Jun 3, 2013, at 7:10 PM, arun wrote: > Hi, > May be this helps: > res1<-df1[with(df1,unlist(tapply(var,list

Re: [R] Read 2 rows in 1 dataframe for diff - longitudinal data

2013-06-03 Thread David Winsemius
On Jun 3, 2013, at 7:10 PM, arun wrote: > Hi, > May be this helps: > res1<-df1[with(df1,unlist(tapply(var,list(subid),FUN=function(x) > c(FALSE,diff(x)!=0)),use.names=FALSE)),] > res1 > # subid year var > #3 36 2003 3 > #7 47 2001 3 > #9 47 2005 1 > #1047 2007 3 > #or

Re: [R] Read 2 rows in 1 dataframe for diff - longitudinal data

2013-06-03 Thread arun
Hi, May be this helps: res1<-df1[with(df1,unlist(tapply(var,list(subid),FUN=function(x) c(FALSE,diff(x)!=0)),use.names=FALSE)),]  res1 #   subid year var #3 36 2003   3 #7 47 2001   3 #9 47 2005   1 #10    47 2007   3 #or library(plyr)  subset(ddply(df1,.(subid),mutate,delta=c(FALSE,di