assign object with loop (translation from SAS to R)

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assign object with loop (translation from SAS to R)

 This post was updated on . I have a dataset named DM with p1, p2, ...., p9 (9 columns, numerical values) I would like to calculate to multify each pair of columns (p1p2, p1p3,... p1p9, p2p3, p2p4.... p8p9) and assign them in p1p2, p1p3,... p1p9, p2p3, p2p4.... p8p9 In SAS, l=0; p_int_sum=0; do i=1 to 8;         do j=(i+1) to 9;         l=l+1;         p{i}p{j}=p{i}*p{j};         end; end; I would like to know how to assign them in R I tried "for" function but had bad luck. for (i in 1:8) { for (j in 2:9) { DM\$p[i]p[j] <- DM\$p[i] * DM\$p[j] }} I would be really grateful if someone can translate it. Thank you so much for reading this!
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Re: assign object with loop (translation from SAS to R)

 Hello, See inline. Em 29-06-2012 02:18, lynx escreveu: > I have a dataset named DM with p1, p2, ...., p9 (9 columns, numerical values) > I would like to calculate to multify each pair of columns (p1p2, p1p3,... > p1p9, p2p3, p2p4.... p8p9) and assign them in p1p2, p1p3,... p1p9, p2p3, > p2p4.... p8p9 > > In SAS, > > l=0; > p_int_sum=0; > do i=1 to 8; > do j=(i+1) to 9; > l=l+1; > p{i}p{j}=p{i}*p{j}; > end; > end; > In R this sort of syntax doesn't work, the trick is to create the variable where to hold the rsult beforehand and use vectors. DM <- data.frame(p=1:9) DM\$prod <- NA  # create results variable i <- 2:9       # use a vector to index DM\$p DM\$prod[i] <- DM\$p[i - 1]*DM\$p[i] DM Hope this helps, Rui Barradas > I would like to know how to assign them in R > I tried for function but failed. > for (i in 1:8) { > for (j in 2:9) { > DM\$p[i]p[j] <- DM\$p[i] * DM\$p[j] > > }} > > Thank you so much for reading this! > > -- > View this message in context: http://r.789695.n4.nabble.com/assign-object-with-loop-translation-from-SAS-to-R-tp4634806.html> Sent from the R help mailing list archive at Nabble.com. > [[alternative HTML version deleted]] > > ______________________________________________ > [hidden email] 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. > ______________________________________________ [hidden email] mailing list https://stat.ethz.ch/mailman/listinfo/r-helpPLEASE do read the posting guide http://www.R-project.org/posting-guide.htmland provide commented, minimal, self-contained, reproducible code.
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Re: assign object with loop (translation from SAS to R)

 In reply to this post by lynx On Jun 28, 2012, at 9:18 PM, lynx wrote: > I have a dataset named DM with p1, p2, ...., p9 (9 columns,   > numerical values) > I would like to calculate to multify each pair of columns (p1p2,   > p1p3,... > p1p9, p2p3, p2p4.... p8p9) and assign them in p1p2, p1p3,... p1p9,   > p2p3, > p2p4.... p8p9 > > In SAS, > > l=0; > p_int_sum=0; > do i=1 to 8; > do j=(i+1) to 9; > l=l+1; > p{i}p{j}=p{i}*p{j}; > end; > end; > > I would like to know how to assign them in R > I tried for function but failed. > for (i in 1:8) { > for (j in 2:9) { # Try instead: DM[[ paste("p",i, "p",j,sep="") ]] <-            DM[[paste("p",i, sep="")]] * DM[[paste("p",i, sep="")]] > DM\$p[i]p[j] <- DM\$p[i] * DM\$p[j] > > }} I suspect there is a more elegant method than this use of R as a macro   processor. I tested the above approach with suitably smalled   subscripts on a smaller dataset: DM <- data.frame(p1=1:10,p2=1:10,p3=1:10,p4=1:10,p5=1:10) -- David Winsemius, MD West Hartford, CT ______________________________________________ [hidden email] mailing list https://stat.ethz.ch/mailman/listinfo/r-helpPLEASE do read the posting guide http://www.R-project.org/posting-guide.htmland provide commented, minimal, self-contained, reproducible code.
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Re: assign object with loop (translation from SAS to R)

 You can use a combination of the outer() and apply() functions n <- 10 p <- 9 dataset <- data.frame(matrix(rep(seq_len(p), each = n), nrow = n, ncol = p)) colnames(dataset) <- paste("p", seq_len(p), sep = "") test <- t(apply(dataset, 1, function(x){ x %o% x})) colnames(test) <- paste("p", rep(seq_len(p), each = p), "p", rep(seq_len(p), p), sep = "") test <- test[, rep(seq_len(p), each = p) < rep(seq_len(p), p)] ir. Thierry Onkelinx Instituut voor natuur- en bosonderzoek / Research Institute for Nature and Forest team Biometrie & Kwaliteitszorg / team Biometrics & Quality Assurance Kliniekstraat 25 1070 Anderlecht Belgium + 32 2 525 02 51 + 32 54 43 61 85 [hidden email] www.inbo.be To call in the statistician after the experiment is done may be no more than asking him to perform a post-mortem examination: he may be able to say what the experiment died of. ~ Sir Ronald Aylmer Fisher The plural of anecdote is not data. ~ Roger Brinner The combination of some data and an aching desire for an answer does not ensure that a reasonable answer can be extracted from a given body of data. ~ John Tukey -----Oorspronkelijk bericht----- Van: [hidden email] [mailto:[hidden email]] Namens David Winsemius Verzonden: vrijdag 29 juni 2012 16:18 Aan: lynx CC: [hidden email] Onderwerp: Re: [R] assign object with loop (translation from SAS to R) On Jun 28, 2012, at 9:18 PM, lynx wrote: > I have a dataset named DM with p1, p2, ...., p9 (9 columns, numerical > values) I would like to calculate to multify each pair of columns > (p1p2, p1p3,... > p1p9, p2p3, p2p4.... p8p9) and assign them in p1p2, p1p3,... p1p9, > p2p3, p2p4.... p8p9 > > In SAS, > > l=0; > p_int_sum=0; > do i=1 to 8; >       do j=(i+1) to 9; >       l=l+1; >       p{i}p{j}=p{i}*p{j}; >       end; > end; > > I would like to know how to assign them in R I tried for function but > failed. > for (i in 1:8) { > for (j in 2:9) { # Try instead: DM[[ paste("p",i, "p",j,sep="") ]] <-            DM[[paste("p",i, sep="")]] * DM[[paste("p",i, sep="")]] > DM\$p[i]p[j] <- DM\$p[i] * DM\$p[j] > > }} I suspect there is a more elegant method than this use of R as a macro processor. I tested the above approach with suitably smalled subscripts on a smaller dataset: DM <- data.frame(p1=1:10,p2=1:10,p3=1:10,p4=1:10,p5=1:10) -- David Winsemius, MD West Hartford, CT ______________________________________________ [hidden email] mailing list https://stat.ethz.ch/mailman/listinfo/r-helpPLEASE do read the posting guide http://www.R-project.org/posting-guide.htmland provide commented, minimal, self-contained, reproducible code. * * * * * * * * * * * * * D I S C L A I M E R * * * * * * * * * * * * * Dit bericht en eventuele bijlagen geven enkel de visie van de schrijver weer en binden het INBO onder geen enkel beding, zolang dit bericht niet bevestigd is door een geldig ondertekend document. The views expressed in this message and any annex are purely those of the writer and may not be regarded as stating an official position of INBO, as long as the message is not confirmed by a duly signed document. ______________________________________________ [hidden email] mailing list https://stat.ethz.ch/mailman/listinfo/r-helpPLEASE do read the posting guide http://www.R-project.org/posting-guide.htmland provide commented, minimal, self-contained, reproducible code.
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Re: assign object with loop (translation from SAS to R)

 With R it is pretty easy to eliminate the loops and the use of outer() (which calculates each product twice) using expand.grid(): > # Create some data and label columns > DM <- data.frame(matrix(round(runif(90)*10, 0), ncol=9)) > colnames(DM) <- paste0("p", 1:9) > > # Create i, j indices and label columns > idx <- expand.grid(2:9, 1:8) > colnames(idx) <- c("j", "i") > > # Compute products in DM2 and label columns > DM2 <- DM[idx\$i]*DM[idx\$j] > colnames(DM2) <- paste0("p", idx\$i, "p", idx\$j) > > # Combine original data with products > DM <- data.frame(DM, DM2) ---------------------------------------------- David L Carlson Associate Professor of Anthropology Texas A&M University College Station, TX 77843-4352 > -----Original Message----- > From: [hidden email] [mailto:r-help-bounces@r- > project.org] On Behalf Of ONKELINX, Thierry > Sent: Friday, June 29, 2012 10:11 AM > To: David Winsemius; lynx > Cc: [hidden email] > Subject: Re: [R] assign object with loop (translation from SAS to R) > > You can use a combination of the outer() and apply() functions > > n <- 10 > p <- 9 > dataset <- data.frame(matrix(rep(seq_len(p), each = n), nrow = n, ncol > = p)) > colnames(dataset) <- paste("p", seq_len(p), sep = "") > test <- t(apply(dataset, 1, function(x){ x %o% x})) > colnames(test) <- paste("p", rep(seq_len(p), each = p), "p", > rep(seq_len(p), p), sep = "") > test <- test[, rep(seq_len(p), each = p) < rep(seq_len(p), p)] > > > > ir. Thierry Onkelinx > Instituut voor natuur- en bosonderzoek / Research Institute for Nature > and Forest > team Biometrie & Kwaliteitszorg / team Biometrics & Quality Assurance > Kliniekstraat 25 > 1070 Anderlecht > Belgium > + 32 2 525 02 51 > + 32 54 43 61 85 > [hidden email] > www.inbo.be > > To call in the statistician after the experiment is done may be no more > than asking him to perform a post-mortem examination: he may be able to > say what the experiment died of. > ~ Sir Ronald Aylmer Fisher > > The plural of anecdote is not data. > ~ Roger Brinner > > The combination of some data and an aching desire for an answer does > not ensure that a reasonable answer can be extracted from a given body > of data. > ~ John Tukey > > -----Oorspronkelijk bericht----- > Van: [hidden email] [mailto:[hidden email]] > Namens David Winsemius > Verzonden: vrijdag 29 juni 2012 16:18 > Aan: lynx > CC: [hidden email] > Onderwerp: Re: [R] assign object with loop (translation from SAS to R) > > > On Jun 28, 2012, at 9:18 PM, lynx wrote: > > > I have a dataset named DM with p1, p2, ...., p9 (9 columns, numerical > > values) I would like to calculate to multify each pair of columns > > (p1p2, p1p3,... > > p1p9, p2p3, p2p4.... p8p9) and assign them in p1p2, p1p3,... p1p9, > > p2p3, p2p4.... p8p9 > > > > In SAS, > > > > l=0; > > p_int_sum=0; > > do i=1 to 8; > >       do j=(i+1) to 9; > >       l=l+1; > >       p{i}p{j}=p{i}*p{j}; > >       end; > > end; > > > > I would like to know how to assign them in R I tried for function but > > failed. > > for (i in 1:8) { > > for (j in 2:9) { > # Try instead: > > DM[[ paste("p",i, "p",j,sep="") ]] <- >            DM[[paste("p",i, sep="")]] * DM[[paste("p",i, sep="")]] > > > DM\$p[i]p[j] <- DM\$p[i] * DM\$p[j] > > > > }} > > I suspect there is a more elegant method than this use of R as a macro > processor. I tested the above approach with suitably smalled subscripts > on a smaller dataset: > > DM <- data.frame(p1=1:10,p2=1:10,p3=1:10,p4=1:10,p5=1:10) > > > -- > David Winsemius, MD > West Hartford, CT > > ______________________________________________ > [hidden email] 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. > * * * * * * * * * * * * * D I S C L A I M E R * * * * * * * * * * * * * > Dit bericht en eventuele bijlagen geven enkel de visie van de schrijver > weer en binden het INBO onder geen enkel beding, zolang dit bericht > niet bevestigd is door een geldig ondertekend document. > The views expressed in this message and any annex are purely those of > the writer and may not be regarded as stating an official position of > INBO, as long as the message is not confirmed by a duly signed > document. > > ______________________________________________ > [hidden email] 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. ______________________________________________ [hidden email] mailing list https://stat.ethz.ch/mailman/listinfo/r-helpPLEASE do read the posting guide http://www.R-project.org/posting-guide.htmland provide commented, minimal, self-contained, reproducible code.