similar to: subtract a specified number of days from current date

Hello, I'm having problems working with date values in POSIXct format. Here is what I got (eg.lig attached): x <- read.table("eg.txt", sep = ',', col.names=c("ok","time","secs","lig")) # it gives time as factor z <- cbind(x,colsplit(x$time, split="\\s", names=c("date", "clock")))

Hello I have this little dataset, my goal is create one column in the data.frame with between the diference DataTime and Duration. I'm using the next code to make do this TIME_STAMP SESSIONTIME Time TimeStart 1162343932 8320 2006-10-31 19:01:34 2006-10-31 16:42:54 1162343215 592 2006-10-31 19:02:04 2006-10-31 18:52:12 1162341465 11875

Hello everybody, how can I reduce e.g. 30 days from a date? When I do the following "2011-05-01 CEST" -"2011-04-01 CEST" I get: "Time difference of 30 days" an thats fine. But when I try "2011-05-01 CEST" - 30 I get nonsense. So how can I subtract some days, month or years from a date? thanking you in anticipation Claudia Paladini

Hello, I have some unbalanced panel data that is measured on weekdays only (i.e., excluding Saturday and Sunday). I would like to get the number of days between dates such that the number of days between a Friday and a Monday is 1 (and not 3). Here is some code to illustrate my problem: library('Hmisc'); DATE <-

Hi, I wanted to calculate the age of people in my dataset by subtracting the individual's date of birth from their intake into a program. After several hours, searches of help archives, and the downloading of lubiridate, I have had no luck with this. Below is the code I used. > intakeDS$DOB <- as.character(intakeDS$DOB) > intakeDS$DOB <- as.Date(intakeDS$DOB,

Hi group, suppose I have a date, say May 15 2004, and I want to now what date it is 23 days before that date. The way to calculate the new date should (...) take account of leap years :) In pseudocode: olddate <- "May 15 2004" newdate <- olddate-23 I looked around in POSIXct etc..., maybe I overlooked? Thanks, Maarten

Hello, I'm trying to write a function that returns the number of weekdays between a vector of start dates and a vector of end dates. Subtracting the 2 times the number of whole weeks is the easy part and works if the number of days is a multiple of 7. However, the number of weekend days in the tail is a little harder. It depends on both the start date of the tail and the number of days in

Hello, I'd have a time series, where I am plotting the means and sd of a distance for a variety of positions along a bird's bill. I'd like to set each line (represented by "point") to start at zero, so that I can look at the absolute change along the series. At the moment I only know how to do that in Excel, by subtracting the value of time 1, point 1 from all other times

Hi all, I am trying to convert all the dates (all days that are not Friday) in data frame into dates to next Friday. The following works but the result is returned as vector rather than the original class. It would be greatly apprecited if you could provide any solution to this problem. Many thanks in advance. # Define arbitrary initial date value ini <- as.Date("2010/1/1",

I am trying to figure out how to create a loop that will take the difference of each member of a vector from each other and also spit out which one has the least difference. I do not want the vector member to subtract from itself or it must be able to disregard the 0 obtained from subtracting from itself. For example: x = c(17,19,23,29) 1. abs(x-x[1]) = (0, 2, 6, 12) 2. abs(x-x[2]) = (2, 0,

Dear R-help I am using R version 2.6.2. I am trying to subtract specific values from a larger data frame. I feel this should be straightforward, but I am struggling. I have a dataframe "Bk" as follows: DateTime cumPrecip 01/01/2008 00:00 348 01/01/2008 01:00 348 01/01/2008 02:00 348 01/01/2008 03:00 347 01/01/2008 04:00 348 01/01/2008 05:00 348 01/01/2008 06:00 349

Hi, I am new to R an dI need some help I have a matrix of real values 100*300 and I would like to calculate the mean for each column , then for each entry in a column i need to subtract the mean so I will have a matrix where the columns have zero mean. any one know how to do that . Thanks -- View this message in context:

there are really two related problems here I have a 2D matrix A <- matrix(1:100,nrow=20,ncol =5) S <- matrix(1:10,nrow=2,ncol =5) #I want to subtract S from A. so that S would be subtracted from the first 2 rows of #A, then the next two rows and so on. #I have a the same problem with a 3D array # where I want to subtract Q for every layer (1-10) in Z # I thought I solved this one

Hi, For example, given two 2x2 matrices m1 and m2. I would like to add/subtract element by element > m1 [,1] [,2] [1,] NA NA [2,] 1 2 > m2 [,1] [,2] [1,] 1 NA [2,] NA 2 > m1 + m2 [,1] [,2] [1,] NA NA [2,] NA 4 How can I ignore the NA, and get this ? Hope the solution can be extended to subtract and modulo also. [,1] [,2]

Dear R experts, I've realized that it might not be possible to define a negative SELCET statement in a SQL call so now I'm looking for the smoothest way to generate a list of what I would like from my large database by first pulling all the names with a query like this "SELECT top 1 * FROM your_table" (thank you Bart Joosen for the idea) and then subtract the variables I am not

Hi everyone, I am having trouble using my own data in the Nash-Sutcliffe efficiency (NSE) function. In R, this is what I have done: Vobsr <- read.csv("Observed_Flow.csv", header = TRUE, sep =",") # see data below Vsimr <- read.csv("1000Samples_Vsim.csv", header = TRUE, sep =",") # see data below Vobsr <- as.matrix(Vobsr[,-1]) # remove column 1

Hi, I have a dataframe wf existing of a header with different labels and beneath the values of those labels : wf: label1 label2 ... 0,45 0,21 0,10 0,45 .... .... I have a list fl <- c("label2","label3",..) Isn't possible to use the list elements in the list in order to subtract values from the dataframe? like : wf$fl[[1]] When I do in R I get :NULL

Dear R users, I have two datasets: id1 <- c(rep(1,10), rep(2,10), rep(3,10)) value1 <- sample(1:100, 30, replace=TRUE) dataset1 <- cbind(id1,value1) id2 <- c(1,2,3) subtract.value <- c(1,3,5) dataset2 <- cbind(id2, subtract.value) I want to subtract the number of rows in the subtract.value that corresponds to the id value in dataset1. So for the 1 in id1, I want to

Apparently any (?) call of the form cut(date,"weeks") where the date *begins the week*, gives the error Error in 1:(1 + max(which(breaks < maxx))) : result would be too long a vector In addition: Warning message: In max(which(breaks < maxx)) : no non-missing arguments to max; returning -Inf To my surprise, this was first reported as a problem in 2006 (!) (version 2.3.1

For the following: Bldgid<-c(1000,1000,1000,1001,1002,1003,1003,1003) Maplot<-c(20000,20001,20002,30000,30001,40000,40001,40002) Area<-c(40,170,160,50,100,100,90,110) #Construct Sample dataframe MultiLotBldgs..<-data.frame(Bldgid,Maplot,Area) CondoLots_ <- tapply(MultiLotBldgs..$Maplot, MultiLotBldgs..$Bldgid, length) CondoLots_ Returns: 1000 1001 1002 1003 3 1 1