similar to: R: simulation

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 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

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

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

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

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

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 =

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, 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

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

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(

I want to calculate a statistic on a number of subgroups of a dataframe, then put the results into a dataframe. (What SAS PROC MEANS does, I think, though it's been years since I used it.) This is possible using by(), but it seems cumbersome and fragile. Is there a more straightforward way than this? Here's a simple example showing my current strategy: > dataset <-

Hi, dear R-helpers, I have a simple question regarding selecting subset of a variable based on another variable. Here is the example: xx=rnorm(10) id=sample(1:10, 10) temp=c(6, 1, 8, 2) Now, all I want is xx's that their id are 6, 1, 8, 2, instead of the position. Any suggestions ? Thank you all your help !! Carrie [[alternative HTML version deleted]]

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) =

hi all i have a simple question: lets assume that i can enter a variable (a) equal to some value, say 100. obviously a could be any value. i would like to create a plot with a main heading as hi all "some writing" + a how would own create a string by combining a string with a numeric variable? hope the question is not too confusing. e.g. say a=5 then i want something like

hi all how does one simulate a random walk process? i.e y(0)=0 y(t)=y(t-1)+ e(t) where e(t) is normal(0,1) say. Regards allan

hi all hopefully some one can help. assume that i imported the following data into R (say the data frame is called a) x1 x2 x3 1 NA 3 1 2 NA 1 2 3 3 NA 6 4 5 9 7 5 6 7 8 9 NA 7 9 How can i construct a new data frame that only contains those rows that does not contain the NA's? is these a quick way? ie x1 x2 x3 1 2 3 4 5 9 7 5 6 7 8 9 in this example we can simple use

a simple question how does one produce plots on two different graphics devices? / allan