similar to: need to delete by time, not date

I have a new device that takes measurements anywhere from every second, to every 15 minutes (depending on changes). The matrix has a date, time and Y column (Y is the measurement). For three days it is 25,000 rows. How do I average the measurements by every 30 minutes so my matrix is 48 rows per day? I have been working on this and cannot figure out a simple method. Any ideas? Thank you. ----- In

I have a combined date and time. I would like to separate them out into two columns so I can do things such as take the mean by time across all dates. meas<-runif(435) nTime<-seq(1303975800, 1304757000, 1800) nDateT<-as.POSIXct(nTime, origin="1970-01-01") mat1<-cbind(nDateT,meas) means1<- aggregate(mat1$meas, list(nDateT), mean) This doesn't do anything as each day

I have x, y, z data. The x, y fields dont change but Z does. How do I add a very small number onto the end of each x, y data point. For example: Original (X) Original (Y) Original (Z) 15 20 30 15 20 40 New (X) New (Y)

I have times and would like to round down to the earliest 30 minute increment. For instance, a time of 2011-04-28 09:02:00 (the as.numeric value = 1303999320) I would like it to be rounded down to: 2011-04-28 09:00:00 (the as.numeric value = 1303999200) Any ideas of how to do this? ----- In theory, practice and theory are the same. In practice, they are not - Albert Einstein -- View this

Hello my friends, here is a code I wrote with no loops on matrix that is taking too long (2 seconds and I call him 720 times --> 12 minutes): mat1 and mat2 are both matrix with 103 columns and 164 rows. sequence <- matrix(seq(1 : ncol(mat1))) returns <- apply(sequence, 1, function, mat1= mat1, mat2 = mat2, day = 1) function<- function(mat1, mat2, colNb, day){

I guess this has a simple solution: I have matrix 'mat1' which has row and column names, e.g.: A B C row1 0 0 0 row2 0 0 0 .... rown 0 0 0 I have a another matrix 'mat2', essentially a subset of 'mat1' where the rownames are all in 'mat1' e.g.: B row3 5 row8 6 row54 7 I want to insert the values of matrix mat2 for column B (in reality it could be some or

Dear R heleprs   Suppose I have following data   Scenarios combination_names     series1    series2 Sc1 MAT2 GAU1 7.26554 8.409778 Sc2 MAT2 GAU2 7.438128 8.130275 Sc3 MAT3 GAU1 8.058422 8.06457 Sc4 MAT1 GAU2 8.179855 8.022071 Sc5 MAT3 GAU2 8.184033 8.191831 Sc6 MAT3 GAU2 7.50312 8.232425 Sc7 MAT1 GAU2 7.603291 8.200993 Sc8 MAT1 GAU1 8.221755 8.380097 Sc9 MAT3 GAU2 7.904908

Hi, I was trying to get error bars in my matplot. I looked at an earlier thread, and the sample code that I made is: #------------------ library(plotrix) mat1 <- matrix(sample(1:30,10),nrow=5,ncol=2) ses <- matrix(sample(1:3,10,replace=T),nrow=5,ncol=2) vect <- seq(20,100,20) rownames(mat1) <- rownames(ses) <- vect colnames(mat1) <- colnames(ses) <- letters[1:2]

Dear List, I often have to merge two or more data frames containing unique row names but with some columns (names) common to the two data frames and some columns not common. This toy example will explain the kind of setup I am talking about: mat1 <- as.data.frame(matrix(rnorm(20), nrow = 5)) mat2 <- as.data.frame(matrix(rnorm(20), nrow = 4)) rownames(mat1) <- paste("site",

Dear useRs, With the following set of command i managed to create the copula density ================================================ >library(MASS) >library(evd) >X<-matrix(sample(1:3000), ncol=2) >U=cbind(rank(X[,1])/(nrow(X)+1),rank(X[,2])/(nrow(X)+1)) > mat1=kde2d(U[,1],U[,2],n=150) image(mat1$x,mat1$y,mat1$z,col= rev(heat.colors(1500)),xlab="",ylab="")

HI, May be this helps: set.seed(24) ?mat1<- matrix(sample(1:60,30*24,replace=TRUE),ncol=24) colnames(mat1)<- rep(c("O","H","L","C"),6) indx<-seq_along(colnames(mat1)) n<- length(unique(colnames(mat1))) ?res<- lapply(split(indx,(indx-1)%%n+1),function(i) mat1[,i]) lapply(res,head,2) #$`1` #????? O? O? O? O? O? O #[1,] 18 56 51 24 24 52 #[2,]

I'm calculating correlations between two matrices mat1 <- matrix(sample(1:500,25), ncol = 5, dimnames=list(paste("mat1row", 1:5, sep=""), paste("mat1col", 1:5, sep=""))) mat2 <- matrix(sample(501:1000,25), ncol = 5, dimnames=list(paste("mat2row", 1:5, sep=""), paste("mat2col", 1:5, sep="")))

Dear all,   I have the following written example > coords <- "51°30'48.58\"N" > > as.integer(strsplit(coords, "°")[[1]][1]) [1] 51 > as.integer(strsplit(strsplit(coords, "°")[[1]][2], "'")[[1]][1]) [1] 30 > as.numeric(strsplit(strsplit(strsplit(coords, "°")[[1]][2], "'")[[1]][2],

Does anyone have information about using the National Practitioner Data Bank (NPDB) in R? It's public use data available from the U.S. Department of Health and Human Services that can be downloaded as a .dat or .por file. I can't even figure out how to open the file in R. [[alternative HTML version deleted]]

Hi, Suppose that I have a list where each component is a list of two matrices. I also have a vector of weights. How can I collapse my list of lists into a single list of two matrices where each matrix in the result is the weighted sum of the corresponding matrices. I could use a loop but this is a nested calculation so I was hoping there is a more efficient way to do this. To help clarify,

Sorry for the verbose example. I want to row bind two matrices, and all works except I want the column labelled "row" to be sequential in the new matrix, shown as "mat3" here, i.e. needs to be 1:6 and not 1:3 repeated twice. Any suggestions? Thanks J > colnm1 <- c("row","ti","counti") > colnm2 <-

Hello, I have a matrix mat1 of dim [1,8] and mat2 of dim[30,8], I want to replace the first row of mat2 with mat1, this is what I do: mat2[1,]<-mat1 but it transforms mat2 in a list I don't understand, I want it to stay a matrix... ----- Anna Lippel -- View this message in context: http://n4.nabble.com/Simple-question-on-replace-a-matrix-row-tp1427857p1427857.html Sent from the R help

A data set I obtained has the hours running from 01 through 24 rather than the conventional 00 through 23. My favorite, strptime, balks at hour 24. I thought it would be easy to correct but it must be too late on Friday for my brain and caffeine isn't helping. TIA for a hint, Clint -- Clint Bowman INTERNET: clint at ecy.wa.gov Air Quality Modeler INTERNET: clint at math.utah.edu

I am stuck on a simple problem where an example works fine but the real one does not. I have a data.frame where I wish to sum up some values across the rows and create a new data.frame with some of old data.frame variables and the new summed variable. It works fine in my simple example but I am doing something wrong in the real world. In the real world I am loading a labeled data.frame. The

HI Eliza, You could do this: set.seed(15) mat1<-matrix(sample(1:800,124*12,replace=TRUE),nrow=12) # smaller dataset #Your codes ?list1<-list() ?for(i in 1:ncol(mat1)){ ? list1[[i]]<-t(apply(mat1,1,function(x) x[i]-x)) ? list1} ?x<-list1?? x<-matrix(unlist(x),nrow=12) x<-abs(x) ?y<-colSums(x, na.rm=FALSE) z<-matrix(y,ncol=10) ?z<-as.dist(z) ?z ?# ?? 1?? 2?? 3?? 4?? 5??