similar to: select subset based on another variable

HI, I am really messing up to make a symmetrical matrix using upper.tri() & lower.tri() function. Here is my code:   > set.seed(1) > mat = matrix(rnorm(25), 5, 5) > mat            [,1]       [,2]       [,3]        [,4]        [,5] [1,] -0.6264538 -0.8204684  1.5117812 -0.04493361  0.91897737 [2,]  0.1836433  0.4874291  0.3898432 -0.01619026  0.78213630 [3,] -0.8356286  0.7383247

Dear all, suppose I have following matrix:   > mat <- matrix(rnorm(25), 5) > > mat             [,1]       [,2]        [,3]       [,4]       [,5] [1,]  0.97056228 -1.3278509 -0.73511792  2.1650629 -0.4411997 [2,]  0.58613700 -0.2559899 -1.18334248 -1.4990907  1.8138846 [3,] -1.03333313  2.0227887  0.89622681  0.6483973 -1.5523283 [4,]  0.38968833  0.2490004 -0.02301061 -0.2705150

Hi. I'm writing a print method for an object that includes a numeric matrix for which the lower diagonal elements are not meaningful. So I make the lower diagonal of my matrix NA and print it. But my co-author does not like NA there and wants a dash. I have tried coercing the matrix to character, essentially by M[is.na(M)] <- "-" but this interferes with the pleasing column

Hello, I am into some calculation on a list object, therefore requesting the peers if there is any short cut way to so the same calculation. Let say I have following list object: > List <- vector('list', length = 3) > set.seed(1) > List[[1]] <- rnorm(5) > List[[2]] <- rnorm(2) > List[[3]] <- rnorm(7) > List [[1]] [1] -0.6264538 0.1836433 -0.8356286

Hi, thanks everyone for any help in advance. I found myself dealing with a tabular time-series data formatted each row like [ time stamp, ID, values]. I made a small examples: X = data.frame(t=c(1,1,1,2,2,2,2,3,3,3,4,4,4,5,5),id =

I want to create a number of vectors like : vec1 <- rnorm(1) vec2 <- rnorm(2) vec3 <- rnorm(3) and so on........... Here I tried following : for (i in 1:10) paste("vec", i, sep="") <- rnorm(i) However obviously that is not working. Here vectors I need to be seperated i.e I do not want to create a "list". How to modify above code? -- View this

Hello, coxph does not use any information that are in the dataset between event times (or "death times") , since computation only occurs at event times. For instance, removing observations when there is no event at that time in the whole dataset does not change the results: > set.seed(1) > data <- as.data.frame(cbind(start=c(1:5,1:5,1:4),stop=c(2:6,2:6,2:5),status=c(rep(

Hello I would like to delete some values at random in a data frame. Does anyone know how I could do? With best regards Caroline

Dear friends, hope I could be able to explain my problem through following example. Please consider this: > set.seed(1) > input <- rnorm(10) > input [1] -0.6264538 0.1836433 -0.8356286 1.5952808 0.3295078 -0.8204684 0.4874291 0.7383247 0.5757814 -0.3053884 > tag <- vector(length=10) for(i in 1:10) # if there is any ****error**** in evaluating

How to force R to print 2 decimal places in column of a data.frame? I tried to do so: x = inp(format(rounf(inp$Tamanho, 2), nsmall = 2),) where "INP" is data.frame and "Size" is the name of column. But has error: Error in eval.with.vis(expr, envir, enclos) : could not find function "inp" Lesandro Veja quais s?o os assuntos do momento no Yahoo! +Buscados

hi all a simple question i want to run simulations in r. i however want the experiments to be repeated at a later time with exactly the same numbers by other users. can i set the random number seed for rnorm in some way? e.g. is there some arguement that goes with rnorm? please supply an example regards Allan

Dear List, I'd appreciate you guidance for obtaining the desired result shown below, by combining tapply(x, g, mean) and g in the example. Basically, I'm trying to create a vector whose values are based on the result from tapply(x, g, mean) but that follow the pattern and length given by the factor g. Of course I'm looking for a generic solution (i.e, not something that just work

Dear all, given two numeric vectors x and y, the ACF(x) at lag k is cor(x(t),x(t+k)) while the CCF(x,y) at lag k is cor(x(t),y(t-k)). See below for a simple example. > set.seed(1) > x <- rnorm(10) > y <- rnorm(10) > x [1] -0.6264538 0.1836433 -0.8356286 1.5952808 0.3295078 -0.8204684 0.4874291 0.7383247 0.5757814 -0.3053884 > y [1] 1.51178117 0.38984324

Hello, which.max() only returns one index value, the one for the maximum value. If I want the two index values for the two largest values, is this a decent solution, or is there a nicer/better R'ish way? max2 <-function(v) { m=which.max(v) v[m] = -v[m] m2=which.max(v) result=c(m, m2) result } Seems to work ok. Thanks, Esmail

Can somebody tell me that, if I do some arithmetic calculation over 2 matrices then how the column names and row names are preserved? It seems that, for multiplication, column names and row names of the 2nd matrix are preserved and for additional, there seems not having any explicit rule: > set.seed(1) > dat1 <- matrix(rnorm(25), 5); colnames(dat1) = rownames(dat1) =

Hello everyone, I have a question about integration of two density function Intuitively, I think the value after integration should be 1, but they are not. Am I missing something here ? > t=function(y){dnorm(y, mean=3)*dnorm(y/2, mean=1.5)} > integrate(t, -Inf, Inf) 0.3568248 with absolute error < 4.9e-06 Also, is there any R function or package could do multivariate integration ?

Hello, everyone, I have a question about integration of product of two densities. Here is the sample code; however the mean of first density is a function of another random variable, which is to be integrated. ## f=function(x) {dmvnorm(c(0.6, 0.8), mean=c(0.75, 0.75/x))*dnorm(x, mean=0.6, sd=0.15)} integrate(f, lower=-Inf, upper=Inf) ## error message Error in dmvnorm(c(0.6, 0.8), mean = c(0.75,

Hello R-helpers, I have a question about counting numbers. Here is a simple example. a=c(2, 3, 3,4) > table(a) a 2 3 4 1 2 1 so, I can to create another variables that has the corresponding counting numbers. In this case, I want to have: b=c(1,2,2,1) Is there any way coding for this ? Thanks for helps! Carrie-- [[alternative HTML version deleted]]

Hi everyone, I am confused regarding the function "density". suppose that there is a sample x of 100 data points, and plot(density(x)) gives it's pdf ? or it's more like histogram only ? thanks for any answering Carrie [[alternative HTML version deleted]]

Dear R-helpers, I am using the package "gee" to run a marginal model. Here is the output. In my simulated data, both x and z are time-varying, so I include their interaction terms with time indicator (i.e. tind=0, if time 1, and 1 if time 2) The data is simulated, so the true parameter of z both at time 1 and time 2 is 5, which is very close from the model output for time 1, z =