ppaarrkk
2008-Dec-09 14:57 UTC
[R] Selecting rows that are the same in separate data frames
I want to compare two matrices or data frames and select or get an index for those rows which are the same in both. I have tried the following : a = matrix ( 1:10, ncol = 2 ) a b = matrix ( c ( 2,3,4,7,8,9 ), ncol = 2 ) b a[a==b] a = as.data.frame ( matrix ( 1:10, ncol = 2 ) ) a b = as.data.frame ( matrix ( c ( 2,3,4,7,8,9 ), ncol = 2 ) ) b a[a==b] Any ideas please. Thanks. Simon Parker Imperial College -- View this message in context: nabble.com/Selecting-rows-that-are-the-same-in-separate-data-frames-tp20916243p20916243.html Sent from the R help mailing list archive at Nabble.com.
bartjoosen
2008-Dec-09 15:23 UTC
[R] Selecting rows that are the same in separate data frames
I'm not sure what you want, but take a look at ?merge and %in% ppaarrkk wrote:> > I want to compare two matrices or data frames and select or get an index > for those rows which are the same in both. I have tried the following : > > > > > > > a = matrix ( 1:10, ncol = 2 ) > a > > b = matrix ( c ( 2,3,4,7,8,9 ), ncol = 2 ) > b > > a[a==b] > > > > > > > a = as.data.frame ( matrix ( 1:10, ncol = 2 ) ) > a > > b = as.data.frame ( matrix ( c ( 2,3,4,7,8,9 ), ncol = 2 ) ) > b > > a[a==b] > > > > > > > > > Any ideas please. > > > Thanks. > > > Simon Parker > Imperial College > >-- View this message in context: nabble.com/Selecting-rows-that-are-the-same-in-separate-data-frames-tp20916243p20916727.html Sent from the R help mailing list archive at Nabble.com.
Jorge Ivan Velez
2008-Dec-09 16:03 UTC
[R] Selecting rows that are the same in separate data frames
Dear Simon, Try this: # Index -- FALSE, TRUE sapply(1:nrow(a),function(x) all(a[x,]%in%b)) # Rows of a that are in b which(sapply(1:nrow(a),function(x) all(a[x,]%in%b))) # Reporting a[sapply(1:nrow(a),function(x) all(a[x,]%in%b)),] HTH, Jorge On Tue, Dec 9, 2008 at 9:57 AM, ppaarrkk <simon_ecc@yahoo.co.uk> wrote:> > I want to compare two matrices or data frames and select or get an index > for > those rows which are the same in both. I have tried the following : > > > > > > > a = matrix ( 1:10, ncol = 2 ) > a > > b = matrix ( c ( 2,3,4,7,8,9 ), ncol = 2 ) > b > > a[a==b] > > > > > > > a = as.data.frame ( matrix ( 1:10, ncol = 2 ) ) > a > > b = as.data.frame ( matrix ( c ( 2,3,4,7,8,9 ), ncol = 2 ) ) > b > > a[a==b] > > > > > > > > > Any ideas please. > > > Thanks. > > > Simon Parker > Imperial College > > -- > View this message in context: > nabble.com/Selecting-rows-that-are-the-same-in-separate-data-frames-tp20916243p20916243.html > Sent from the R help mailing list archive at Nabble.com. > > ______________________________________________ > R-help@r-project.org mailing list > stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide > R-project.org/posting-guide.html > and provide commented, minimal, self-contained, reproducible code. >[[alternative HTML version deleted]]
Henrique Dallazuanna
2008-Dec-09 16:15 UTC
[R] Selecting rows that are the same in separate data frames
Try this: 1) Rows: merge(as.data.frame(a), as.data.frame(b), sort = FALSE) 2) Index: merge(cbind(as.data.frame(a), Idx = 1:nrow(a)), as.data.frame(b), sort FALSE)$Idx On Tue, Dec 9, 2008 at 12:57 PM, ppaarrkk <simon_ecc@yahoo.co.uk> wrote:> > I want to compare two matrices or data frames and select or get an index > for > those rows which are the same in both. I have tried the following : > > > > > > > a = matrix ( 1:10, ncol = 2 ) > a > > b = matrix ( c ( 2,3,4,7,8,9 ), ncol = 2 ) > b > > a[a==b] > > > > > > > a = as.data.frame ( matrix ( 1:10, ncol = 2 ) ) > a > > b = as.data.frame ( matrix ( c ( 2,3,4,7,8,9 ), ncol = 2 ) ) > b > > a[a==b] > > > > > > > > > Any ideas please. > > > Thanks. > > > Simon Parker > Imperial College > > -- > View this message in context: > nabble.com/Selecting-rows-that-are-the-same-in-separate-data-frames-tp20916243p20916243.html > Sent from the R help mailing list archive at Nabble.com. > > ______________________________________________ > R-help@r-project.org mailing list > stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide > R-project.org/posting-guide.html > and provide commented, minimal, self-contained, reproducible code. >-- Henrique Dallazuanna Curitiba-Paraná-Brasil 25° 25' 40" S 49° 16' 22" O [[alternative HTML version deleted]]