Are you sure its a matrix? or is it a data frame? > BOD # built into R Time demand 1 1 8.3 2 2 10.3 3 3 19.0 4 4 16.0 5 5 15.6 6 7 19.8 > class(BOD) [1] "data.frame" > BOD[2] demand 1 8.3 2 10.3 3 19.0 4 16.0 5 15.6 6 19.8 > BOD[[2]] [1] 8.3 10.3 19.0 16.0 15.6 19.8 > BOD[,2] [1] 8.3 10.3 19.0 16.0 15.6 19.8 > bod <- as.matrix(BOD) > class(bod) [1] "matrix" > bod[2] [1] 2 > bod[,2] [1] 8.3 10.3 19.0 16.0 15.6 19.8
You may wish to review the Introduction to R manual and the many contributed introductions at the first hit found by googling for CRAN contributed documentation On Nov 24, 2007 9:07 AM, Denver XU <[EMAIL PROTECTED]> wrote: > Hi, R-users, > data is a matrix like this > AMR BS GE HR MO UK SP500 > 1974 -0.3505 -0.1154 -0.4246 -0.2107 -0.0758 0.2331 -0.2647 > 1975 0.7083 0.2472 0.3719 0.2227 0.0213 0.3569 0.3720 > 1976 0.7329 0.3665 0.2550 0.5815 0.1276 0.0781 0.2384 > 1977 -0.2034 -0.4271 -0.0490 -0.0938 0.0712 -0.2721 -0.0718 > 1978 0.1663 -0.0452 -0.0573 0.2751 0.1372 -0.1346 0.0656 > 1979 -0.2659 0.0158 0.0898 0.0793 0.0215 0.2254 0.1844 > 1980 0.0124 0.4751 0.3350 -0.1894 0.2002 0.3657 0.3242 > 1981 -0.0264 -0.2042 -0.0275 -0.7427 0.0913 0.0479 -0.0491 > 1982 1.0642 -0.1493 0.6968 -0.2615 0.2243 0.0456 0.2141 > 1983 0.1942 0.3680 0.3110 1.8682 0.2066 0.2640 0.2251 > I want to calculate the return say AMR,so I use > re=numeric(10) > for (i in 2:nrow(data)) > re[1]=0 > re[i]=log(data[i]/data[i-1]) > to my surprise, the result is > > re > [1] 0.00000 0.00000 0.00000 0.00000 0.00000 0.00000 0.00000 0.00000 > [9] 0.00000 -1.70109 > I don't know what's wrong with my code, and is there alternative way > to do the same? > thanks > > Denver > > ______________________________________________ > R-help@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. > ______________________________________________ R-help@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.