Hi, Is there an expression to double the values of a matrix - without using a loop? What I need is this: Suppose we have this matrix> m[,1] [,2] [,3] [1,] 7 17 4 [2,] 11 10 18 [3,] 15 19 18 and I want this matrix [,1] [,2] [,3] [1,] 112 102 115 [2,] 108 109 101 [3,] 104 100 101 where for instance, m[1,1] was obtained by adding (7+17+4+11+10+18+15+19+18)-7 with this loop I am able to get the result I need but I wanted to know if a more R way of doing this.> a<-matrix(c(7,17,4,11,10,18,15,19,18),3,3,T) > m=a > for(i in 1:9){+ m[c(i)]<-sum(a)-a[c(i)] + }> mthanks AD -- View this message in context: http://r.789695.n4.nabble.com/How-to-doulbe-all-the-value-on-a-matrix-tp3221213p3221213.html Sent from the R help mailing list archive at Nabble.com.
If I have understood your question correctly, how about the following ... m = matrix(c(7,11,15,17,10,19,4,18,18), nrow = 3, ncol=3) sum_m = sum(m) new_m = summ-m HTH Pete -- View this message in context: http://r.789695.n4.nabble.com/How-to-doulbe-all-the-value-on-a-matrix-tp3221213p3221215.html Sent from the R help mailing list archive at Nabble.com.
typo ... should have been m = matrix(c(7,11,15,17,10,19,4,18,18), nrow = 3, ncol=3) sum_m = sum(m) new_m = sum_m-m -- View this message in context: http://r.789695.n4.nabble.com/How-to-doulbe-all-the-value-on-a-matrix-tp3221213p3221216.html Sent from the R help mailing list archive at Nabble.com.
Hi, yes it works perfectly. I have another question: Is there way of selecting with a vector the values I wish to take out from a matrix. Example: I have this matrix and I want to take out the numbers in bold and get the second matrix below>m[,1] [,2] [,3] [,4] [,5] [,6] [,7] [,8] [,9] [,10] [1,] 17 1 6 5 19 2 19 1 15 8 [2,] 7 7 20 3 2 16 9 9 19 13 [3,] 2 4 3 11 18 11 14 13 3 1 [4,] 3 7 5 7 17 18 10 6 5 15 [5,] 8 20 13 10 8 12 20 19 1 16 [6,] 9 14 1 12 12 12 17 18 10 17 [7,] 3 10 11 2 12 9 18 6 19 9 [8,] 13 2 17 16 18 8 9 14 9 16 [9,] 9 4 11 4 1 17 9 7 20 12 [10,] 9 1 4 8 8 19 19 8 17 18 [,1] [,2] [,3] [,4] [1,] 7 3 16 9 [2,] 3 2 9 18 [3,] 13 16 8 9 thanks AD -- View this message in context: http://r.789695.n4.nabble.com/How-to-doulbe-all-the-value-on-a-matrix-tp3221213p3221230.html Sent from the R help mailing list archive at Nabble.com.
ADias wrote:> > Is there an expression to double the values of a matrix - without using a > loop? > >Why so complicated? Dieter> m = matrix(rep(1,20),nrow=4) > m[,1] [,2] [,3] [,4] [,5] [1,] 1 1 1 1 1 [2,] 1 1 1 1 1 [3,] 1 1 1 1 1 [4,] 1 1 1 1 1> m*3[,1] [,2] [,3] [,4] [,5] [1,] 3 3 3 3 3 [2,] 3 3 3 3 3 [3,] 3 3 3 3 3 [4,] 3 3 3 3 3>-- View this message in context: http://r.789695.n4.nabble.com/How-to-doulbe-all-the-value-on-a-matrix-tp3221213p3221231.html Sent from the R help mailing list archive at Nabble.com.
try ... new_m = m[c(2,7,8),c(1,4,6,7)] HTH Pete -- View this message in context: http://r.789695.n4.nabble.com/How-to-doulbe-all-the-value-on-a-matrix-tp3221213p3221234.html Sent from the R help mailing list archive at Nabble.com.
On Jan 17, 2011, at 11:16 AM, ADias wrote:> > Hi, > > yes it works perfectly. > > I have another question: > > Is there way of selecting with a vector the values I wish to take > out from a > matrix. > > Example: > > I have this matrix and I want to take out the numbers in bold and > get the > second matrix belowThis is a plain text mailing list (despite what the Nabble mirror may (mis-)lead you into believing) ... no bold. -- david.> >> m > [,1] [,2] [,3] [,4] [,5] [,6] [,7] [,8] [,9] [,10] > [1,] 17 1 6 5 19 2 19 1 15 8 > [2,] 7 7 20 3 2 16 9 9 19 13 > [3,] 2 4 3 11 18 11 14 13 3 1 > [4,] 3 7 5 7 17 18 10 6 5 15 > [5,] 8 20 13 10 8 12 20 19 1 16 > [6,] 9 14 1 12 12 12 17 18 10 17 > [7,] 3 10 11 2 12 9 18 6 19 9 > [8,] 13 2 17 16 18 8 9 14 9 16 > [9,] 9 4 11 4 1 17 9 7 20 12 > [10,] 9 1 4 8 8 19 19 8 17 18 > > [,1] [,2] [,3] [,4] > [1,] 7 3 16 9 > [2,] 3 2 9 18 > [3,] 13 16 8 9 > > thanks > AD > > -- > View this message in context: http://r.789695.n4.nabble.com/How-to-doulbe-all-the-value-on-a-matrix-tp3221213p3221230.html > Sent from the R help mailing list archive at Nabble.com. > > ______________________________________________ > R-help at r-project.org 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.David Winsemius, MD West Hartford, CT