Hi-
I am trying to create a table of values by adding pairs of vectors, but am running into some problems. The problem is best expressed by a simple example. Starting with a data table "basis": atom x y z 1 Cu 0.0 0.0 0.0 2 Cu 0.5 0.5 0.5 I want to add 0.5 0.5 0.5 (and also the 0 0 0 but it wouldn't change the values below so I won't refer to it in the rest of the example) to a list of vectors in the form of: > latpoints V1 V2 V3 1 0 0 0 2 0 0 1 3 0 0 2 4 0 0 3 5 0 1 1 so that I end up with a table such as: V1 V2 V3 0.5 0.5 0.5 0.5 0.5 1.5 0.5 0.5 2.5 0.5 0.5 3.5 0.5 1.5 1.5 I've tried many variations on the following: (not just cat, but most of the data/data.table options) test = for(i in 1:5) {cat(basis[1,2:4] + latticemultipliers[i,], append=TRUE)} However, I either end up with an error telling me that cat doesn't handle "type 'list' " or with a table with length of 1 such as: x y z 2 0.5 1.5 1.5 Which is simply the last value that the loop calculates. Does anyone know what function handles lists of the form I am using, or have a better suggestion on how to get the form that I want. Thanks in advance, Seth Imhoff ______________________________________________ [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. |
Your "data table" basis is actually a dataframe, whose first column is
non-numeric. That's what is causing the problem. Try removing the first column of the dataframe before adding the row to your matrix: test <- latpoints + basis[2, -1] -Christos Christos Hatzis, Ph.D. Nuvera Biosciences, Inc. 400 West Cummings Park Suite 5350 Woburn, MA 01801 Tel: 781-938-3830 www.nuverabio.com > -----Original Message----- > From: [hidden email] > [mailto:[hidden email]] On Behalf Of Seth Imhoff > Sent: Friday, March 09, 2007 9:23 PM > To: [hidden email] > Subject: [R] Table Construction from calculations > > Hi- > > I am trying to create a table of values by adding pairs of > vectors, but am running into some problems. The problem is > best expressed by a simple example. > > Starting with a data table "basis": > atom x y z > 1 Cu 0.0 0.0 0.0 > 2 Cu 0.5 0.5 0.5 > > I want to add 0.5 0.5 0.5 (and also the 0 0 0 but it > wouldn't change the values below so I won't refer to it in > the rest of the example) to a list of vectors in the form of: > > latpoints > V1 V2 V3 > 1 0 0 0 > 2 0 0 1 > 3 0 0 2 > 4 0 0 3 > 5 0 1 1 > > so that I end up with a table such as: > V1 V2 V3 > 0.5 0.5 0.5 > 0.5 0.5 1.5 > 0.5 0.5 2.5 > 0.5 0.5 3.5 > 0.5 1.5 1.5 > > I've tried many variations on the following: (not just cat, > but most of the data/data.table options) > > test = for(i in 1:5) {cat(basis[1,2:4] + > latticemultipliers[i,], append=TRUE)} > > However, I either end up with an error telling me that cat > doesn't handle "type 'list' " or with a table with length of > 1 such as: > x y z > 2 0.5 1.5 1.5 > > Which is simply the last value that the loop calculates. > > Does anyone know what function handles lists of the form I am > using, or have a better suggestion on how to get the form that I want. > > Thanks in advance, > Seth Imhoff > > ______________________________________________ > [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-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code. |
In reply to this post by Seth Imhoff
On Mar 9, 2007, at 9:23 PM, Seth Imhoff wrote:
> I am trying to create a table of values by adding pairs of > vectors, but > am running into some problems. The problem is best expressed by a > simple example. > > Starting with a data table "basis": > atom x y z > 1 Cu 0.0 0.0 0.0 > 2 Cu 0.5 0.5 0.5 > > I want to add 0.5 0.5 0.5 (and also the 0 0 0 but it wouldn't change > the values below so I won't refer to it in the rest of the example) > to a > list of vectors in the form of: >> latpoints > V1 V2 V3 > 1 0 0 0 > 2 0 0 1 > 3 0 0 2 > 4 0 0 3 > 5 0 1 1 > > so that I end up with a table such as: > V1 V2 V3 > 0.5 0.5 0.5 > 0.5 0.5 1.5 > 0.5 0.5 2.5 > 0.5 0.5 3.5 > 0.5 1.5 1.5 > > I've tried many variations on the following: (not just cat, but > most of > the data/data.table options) > > test = for(i in 1:5) {cat(basis[1,2:4] + latticemultipliers[i,], > append=TRUE)} > > However, I either end up with an error telling me that cat doesn't > handle "type 'list' " or with a table with length of 1 such as: > x y z > 2 0.5 1.5 1.5 Is this what you want? > (latpoints <- data.frame(matrix(c(0,0,0,0,0,1,0,0,2,0,0,3,0,1,1), nrow = 5, byrow = T))) X1 X2 X3 1 0 0 0 2 0 0 1 3 0 0 2 4 0 0 3 5 0 1 1 > (latpoints <- latpoints + c(0.5, 0.5, 0.5)) X1 X2 X3 1 0.5 0.5 0.5 2 0.5 0.5 1.5 3 0.5 0.5 2.5 4 0.5 0.5 3.5 5 0.5 1.5 1.5 This is an important feature of R called "vectorization" (see, .e.g, cran.r-project.org/doc/contrib/Paradis-rdebuts_en.pdf or www.ms.washington.edu/stat390/winter07/R_primer.pdf) which allows you do avoid writing loops. _____________________________ Professor Michael Kubovy University of Virginia Department of Psychology USPS: P.O.Box 400400 Charlottesville, VA 22904-4400 Parcels: Room 102 Gilmer Hall McCormick Road Charlottesville, VA 22903 Office: B011 +1-434-982-4729 Lab: B019 +1-434-982-4751 Fax: +1-434-982-4766 WWW: http://www.people.virginia.edu/~mk9y/ ______________________________________________ [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. |
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