similar to: Matrix multiplication by multple constants

Dear R list, I have one very elementary question regrading correlation between two variables. x = c(44,46,46,47,45,43,45,44) y = c(44,43,41,41,46,48,44,43) > cov(x, y) [1] -2.428571 However, if I try to calculate the covariance using the formula as covariance = sum((x-mean(x))*(y-mean(y)))/8       # no of of paired obs. = 8 or     covariance = sum(x*y)/8-(mean(x)*mean(y)) gives

Dear Group, I have a following dataset: > a A B C D 1 22 3 31 40 2 26 31 36 32 3 3 7 49 16 4 24 40 27 26 5 20 45 47 0 6 34 43 11 18 7 48 48 24 2 8 3 16 39 48 9 20 49 7 21 10 17 36 47 10 > dput(a) structure(list(A = c(22L, 26L, 3L, 24L, 20L, 34L, 48L, 3L, 20L, 17L), B = c(3L, 31L, 7L, 40L, 45L, 43L, 48L, 16L, 49L, 36L), C = c(31L, 36L, 49L, 27L, 47L, 11L, 24L,

Dear All, I would appreciate any help with the following: given the vector 'x' x <- c("Ass1", "Ass.s1", "Ass2", "Ass.s2") I would like to pick up the positions where the character string contains "Ass" but does not contain "Ass.s", so for 'x' that would be positions 1 and 3. I guess this could be programmed around

Hi, I have this lame question. I want to convert a list (each with varies in length) to matrix with same row length by eliminating vectors outside the needed range. For example: l<-list(NULL) l[[1]]=1,2,3.7 l[[2]]=3,4,5,6,3 l[[3]]=4,2,5,7 l[[4]]=2,4,6,3,2 l[[5]]=3,5,7,2 #so say I want to only have 4 rows and 5 column in my matrix (or data.frame) and eliminating the 5th index value in l[[2]]

Dear all I have data like this: x y [1,] 59.74889 3.1317081 [2,] 38.77629 1.7102589 [3,] NA 2.2312962 [4,] 32.35268 1.3889621 [5,] 74.01394 1.5361227 [6,] 34.82584 1.1665412 [7,] 42.72262 2.7870875 [8,] 70.54999 3.3917257 [9,] 59.37573 2.6763249 [10,] 68.87422 1.9697770 [11,] 19.00898 2.0584415 [12,] 60.27915 2.5365194 [13,] 50.76850

Hi all, I am trying to multiply each column of a matrix such to have a unique resulting vector with length equal to the number of rows of the original matrix. In short I would like to do what prod(.) function in Matlab does, i.e. A <-matrix(c(1:10),5,2) V = A[,1]*A[,2] Thank you Graziano [[alternative HTML version deleted]]

Hello, I have a function with a long list of parameters (of different types, numeric and string) myFunc <-function(p1, p2, p3, p4, p5...etc) { do.something(p1,p2,....) } I want to loop over this to provide a different set of parameters to the list every time. for (ii in 1:N) { myFunc(p1(ii), p2(ii),....etc) } I would like to simplify the notation and use some kind of structure, maybe

[My previous message rejected, therefore I am sending same one with some modification] I have 3 vectors with object name : dat1, dat2, dat3 Now I want to create a loop, like : for (i in 1:3) { cat(sd(dati)) } How I can do this in R? Regards,

Hello, I am stuck with the following problem. Consider the vector: vec <- c(2,4,6,9,10) I now want to use R to manipulate the vector as follows: [1] 2, 4, 2, 6, 2, 9, 2, 10 In words, the first element of the vector should be placed in front of each following number. Which R commands do I need to achieve that? Cheers -- View this message in context:

Hi, Not sure how to go about checking for missing report pages per client. See example below; I like to extract client 730040, because page 46103 is missing. client page 730001 46101 730001 46102 730019 46101 730035 46101 730040 46101 730040 46102 730040 46104 730040 46105 730052 46101 730052 46102 730074 46101 730074 46102 730074 46103 I appreciate any help, Pauline

A list contains several matrices. Over all matrices (list elements) I'd like to access one matrix cell: m <- matrix(1:9, nrow=3, dimnames=list(LETTERS[1:3], letters[1:3])) l <- list(m1=m, m2=m*2, m3=m*3) l[[3]] # works l[[3]][1:2, ] # works l[[1:3]][1, 1] # does not work How can I slice all C-c combinations in the list? S?ren -- S?ren Vogel, Dipl.-Psych. (Univ.), PhD-Student, Eawag,

Hello R-help, Please cc me on all responses, as I only receive summary emails from this list. I'm wondering if anybody has any tips on how to accomplish this efficiently. I have a list of matrices, and I'm trying to get the mean of the [i,j]'th element of each matrix in a list. So if I have a list of matrices, say x <-

Hi everyone. I would like to modify the axis on my plot. First, I would like to make a plot without the box. so I use : plot(x,y, axes = FALSE, type = 'l') Then, I call : axis(1, tck = -0.02) axis(2, tck = -0.02) to have X and Y axis appear. However, I would like them to join at the origin instead of having a space between the 2 axis. I can't find the parameter to modify to get

Dear list, I would like to expand a DF with all the missing levels of a variable. a <- c(2,2,3,4,5,6,7,8,9) a.cut <- cut(a, breaks=c(0,2,6,9,12), right=FALSE ) (x <- data.frame(a, a.cut)) # In 'x' the level "[0,2)" is "missing". AddMissingLevel <- function(xdf) { xfac <- factor( c("[0,2)", "[2,6)", "[6,9)",

Hi All, What is the fastest way of finding if any members of vector x fall in the range of the rows of matrix y? I do not want to use two for loops as this will take forever. Any help will be appreciated, best, salih [[alternative HTML version deleted]]

Hello everyone, I need to fit a bivariate normal regression model to a dataset where the same covariate (say, X) influences two separate but correlated responses (say, Y1 and Y2). So, the bivariate model would look like : Y1 = a1 + b1*X + e1 Y2 = a2 + b2*X + e2 where e1 and e2 are error terms which can be correlated. Is there any package in R which can help me fit this model ? Any help will be

dear R community, i appologize as this is kind of a newbie question, but: I want to assign group letters (like in anova post-hoc tests) to data with combined means and SDs. It's easy to apply t-test formulas to get a materix like (A - D are treatments | A B C D ----------------------- A| T F F B| T F C| F D| where true stands for sign.

Hi Guys, Does anyone know how I could constrain my regression coefficients so that they are positive and add up to one? Any help will be greatly appreciated. Kind Regards, Andre [[alternative HTML version deleted]]

hello, i am familiar with the paste command with which i can paste for exaple: object <- "Hello" paste(object,"World") now i would like to be able to paste all the elements of the same vector together e.g: object <- c("Hello","World") getting as a result also: "Hello World". Does anyone know the solution to this problem? Thank you

hello everybody, i have got a question about lists: i have got the following commands: mylist <- list("v1"=c(1,2,2,1),"v2"=c(2,2,2,1),"v3"=c(1,1,1,1)) myvector <- c(100,10000,1000000) now i would like to multiply each element of the list with the corresponding element of the vector, that is to say: v1*100 v2*10000 v3*1000000 i only could think of lapply