similar to: how to add a derived column to a data frame?

Hi, Can someone tell me how to remove rows of zeros from a matrix? For example if I have the following matrix, 0 0 0 1 2 8 0 0 4 56 I should end up with 0 1 2 8 4 56 -- Thanks, Jim. [[alternative HTML version deleted]]

Dear all, suppose I have a vector with elements as: Vec <- c(2,3,4,5,6) Now I want to have all possible combination of length 3 using those elements and without any repetition. Like, I want to have 1 possibility like 2-3-4 but not 3-2-4. Can somebody guide me how to achieve that in R? Thanks for your help.

List members, Via searches I've seen similar discussion of this topic but have not seen resolution of the particular issue I am experiencing. If my search on this topic failed, I apologize for the redundancy. I am attempting to generate random covariance matrices but would like the corresponding correlations to be uniformly distributed between -1 and 1. The approach I have been using is:

Hello everybody! I’m trying to define the optimal number of surveys to detect the highest number of species within a monitoring season/session. To do this I want to run all the possible combinations between a set of samples and to calculate the total number of species for each combination of 2, 3, 4 …n samples events, so that at the end I will be able to define which is the lowest number of

Hi, I'm new to R and trying to some simple analysis. I have a data set with about 88000 transactions and i want to perform a simple support count analysis of an itemset which is say not a complete transaction but a subset of a transaction. say {A,B,D} is a transaction and i want to find support of {A,B} even though it never occurs as only A,B in the entire set To this i needed to create

Two posts in one day is not a good day...and this question seems like it should have an obvious answer: I have a matrix where rows are unique combinations of 1's and 0's: > combs=as.matrix(expand.grid(c(0,1),c(0,1))) > combs Var1 Var2 [1,] 0 0 [2,] 1 0 [3,] 0 1 [4,] 1 1 I want a single function that will give the row index containing an exact match

Hi all, Lets say I have a matrix A which is m x n. I also have a mask matrix MASK which is m x n with values in T/F, where T values make a sub-matrix in regutangular shape... I applied B=A[MASK] and it didn't work as expected... Any thoughts? [[alternative HTML version deleted]]

Hi, I have a matrix, say m=matrix(c( 983,679,134, 383,416,84, 2892,2625,570 ),nrow=3 ) i can find its row/col sum by rowSums(m) colSums(m) How do I divide each row/column by its rowSum/colSums and still return in the matrix form? (i.e. the new rowSums/colSums =1) Thanks. Casper -- View this message in context:

Hello All, Want very much to learn how to plot patient drug timelines. Trouble is I need to figure out how to do this today. So not much time for me to struggle with it. Hoping someone can just help me out a bit. Below are some sample data and code that produces what I think is the beginning of a very nice graph. Need to alter the code to: 1. Get the lines for the drugs to appear on the

Dear All, I am evaluating the value of loglikelihood and it ends up with the sum of tiny numbers. Below is an example: suppose I would like to calculate sum_i (log (sum_j x [i, j] )), the index of log (x) is in the range, say (-2000, 0). I am aware that exp(-744.5) will be expressed as 0 in 32 bit R and exp Is there a way to improve the result? R example: powd <- sample(-2000:0, 100,

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Dear All, I am trying to fill in a blank vector ("a") with one value at a time, with the value of the number of rows in a randomized dataset with rowSums=0. Below is the code I've got so far, but what I want to be as the last line is " a[1st NA,]=nz" such that this will run until all of my NAs are replaced with an integer value based on randomizations.

I am a new user of R package and I needed a help regarding plotting confidence limits for FFT ( chisquare based) and spectrum using the monte carlo simulations of background red noise . How do I do it in R can any one help in this issue? sudheer º¤ø,¸¸,ø¤º°`°º¤ø,¸¸,ø¤º°`°º¤ø,¸¸,ø¤º°`°º¤º¤ø,¸¸,ø¤º Sudheer Joseph Scientist Indian National Centre for Ocean Information Services

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:::Happy mail::: Happymail ¹× ±âŸ ¹®ÀÇ 02-588-0510 2002³â 1¿ù ¢Ã Ä£±¸ÀÇ Ãæ°í ¢Ñ [¿µ¾î·Î ¿ô¾î¿ä] ¿ø¹®º¸±â A man and his friend were travelling on a train. They decided they were hungry and each took out a banana. Just as the first man took a bite of his, the train entered a tunnel and everything went dark. The man said to

Hello, I have a R code for doing convolution of two functions: convolveSlow <- function(x, y) { nx <- length(x); ny <- length(y) xy <- numeric(nx + ny - 1) for(i in seq(length = nx)) { xi <- x[[i]] for(j in seq(length = ny)) { ij <- i+j-1 xy[[ij]] <- xy[[ij]] + xi * y[[j]] } } xy } How do I reduce the 2

Dear list users, let me ask you this trivial question. I worked on that for a long time, by now. Suppose to have a data frame with NAs and to sum some columns with rowSums: df <- data.frame(A = runif(10), B = runif(10), C = rnorm(10)) df[1, ] <- NA rowSums(df[ , which(names(df) %in% c("A","B"))], na.rm=T) If all the elements of the selected columns are NA, rowSums