similar to: difftime result in years?

I am a bit worried I am reinventing the wheel. Isn't there a calendar system in R? I have written a function to add months to a date and return the number of days resulting. I am newish to R so I am hoping there is a package that can do this sort of date arithmetic for me... Worik DaysInMonths <- function(s,d){ ## Days in d months from s sdate <- MSTD(s) ## Get day, month

It seems obvious to me that the empty string "" is length 0. cheers Worik [[alternative HTML version deleted]]

I have trouble with this: as.Date("Sep-1981", format="%b-%Y") Returns "NA" >From documentation for strftime '%b' Abbreviated month name in the current locale. (Also matches full name on input.) '%Y' Year with century. What am I doing wrong? cheers Worik [[alternative HTML version deleted]]

I cannot find out how to build data structures as lists of data structures. I want to do... r-help@r-project.org d1 <- data.frame(x=1, y=2) d2 <- data.frame(x=1, y=3) d3 <- data.frame(x=21, y=3) q1 <- data.frame(q=d1, n="a") q2 <- data.frame(q=d2, n="a") q3 <- data.frame(q=d3, n="a") v <- vector() or list() or whatever v[1] <- q1 v[2]

I have two pairs of related vectors x1,y1 and x2,y2 I wish to do a test for differences in means of x1 and y1, ditto x2 and y2. I am getting odd results. I am not sure I am using 'pt' properly... I have not included the raw vectors as they are long. I am interested if I am using R properly... > c(length(x1), length(y1), length(x2), length(y2)) [1] 3436 1619 2677 2378 First

I think I am whistling in the wind, but is there a modern symbolic debugger for R programmes? I am working through some one else's code, thousands of lines, that has the occasional bug in it, and a lot in my understanding of it. I cannot make setBreakpoint or findLineNum work. I get "No source refs found.". I am starting to loose my mind! A debugger where I could set

Full_Name: Barry Rowlingson Version: 1.6.0 OS: RH8 i386 Submission from: (NULL) (148.88.136.205) Strange things happen if I premultiply a difftime() object with a number. Example: > d1 <- difftime(Sys.time(),Sys.time()) > d2 <- 1 * difftime(Sys.time(),Sys.time()) > d3 <- difftime(Sys.time(),Sys.time()) * 1 > d1 Time difference of 0 secs - thats fine > d2 [1] 0

I am puzzled by the scope rules that apply with sapply. If I want to modify a vector with sapply I tried... N <- 10 vec <- vector(mode="numeric", length=N) test <- function(i){ vec[i] <- i } sapply(1:N, test) vec but it not work. How can this be done? Worik [[alternative HTML version deleted]]

Friends I clearly donot understand how sapply and vapply work. What I have is a function that returns a matrix with an indeterminate number of rows (some times zero) but a constant number of columns. I cannot reliably use an apply function to assemble the matrices into a matrix. I am not sure it is possible. I can demonstrate the core of my confusion with this simple code. A.f <-

Friends I am looking at Rcpp and I am a bit stuck on a simple matter. (I am calling R from c++, if there is a better way...) Given this simple example using the TTR package and the SMA function which returns a simple moving average.... Rcpp::NumericVector rv; for(int i = 0; i < 100; i++){ rv.push_back(rand()); } Rcpp::Environment TTR("package:TTR");

I have a large programme that after running half an hour or so fails with an error Error in x[value] <- NA : only 0's may be mixed with negative subscripts How can I find out where that error occurs? If I have to do a binary search using error messages it will take a long time! Is there some way I can generate a stack trace? cheers Worik [[alternative HTML version deleted]]

How can I increment the value of a Date class? I want to add a day, month or year to a date. cheers Worik [[alternative HTML version deleted]]

Friends I am trying to format a number to a string so 2189.745 goes to "2,189.35" and 309283.929 goes to "309,283.93" I have tried to use formatC(X, big.mark=",",drop0trailing=FALSE, format="f") but it does not get the number of decimals correct. Specifying digits does not work as that is significant digits. I could use a switch statement switching on

Is it possible to get a line number with an error report? I have a long script and an error: Error in `[.xts`(x, xsubset) : subscript out of bounds It would be very helpful, and save a lot of time, if there was some indication in the error message which line the error was. I can find it using binary search but that is a painful process. cheers Worik [[alternative HTML version deleted]]

Friends I have an xts that I wish to access. Browse[2]> DATA.ba[[p]]["2012-03-20 00:59:57","bid"] bid 2012-03-20 00:59:57 1.4993 So far so good. Now putting the index into a variable: Browse[2]> Time [1] "2012-03-20 00:59:57 NZDT" Browse[2]> DATA.ba[[p]][Time, "bid"] bid Where has it gone? Looking closer....

If I create a vector thusly > v1 <- runif(20, min=0, max=1) > v1 [1] 0.9754443 0.6306228 0.3238158 0.3175769 0.6791534 0.6956507 0.3840803 [8] 0.1421328 0.8592398 0.4388306 0.9472040 0.4727435 0.5645302 0.7391616 [15] 0.6116199 0.2727754 0.2657867 0.5261744 0.8764804 0.2032126 And I want to create a logical vector the same length that is true if v1<.3 or v1 > .7 how do I do it

Friends I am starting on a (section of the) project where I need to build a matrix with on the order of 5 million rows and 200 columns I am wondering if I can stay in R. I need to do rollapply type operations on the columns, including some that will be functions of (windows of) two columns. I have been looking at the ff and bigmemory packages but am not sure that they will do. Before I get

Is there a simple way to put a legend outside the plot area for a simple plot? I found... (at http://www.harding.edu/fmccown/R/) # Expand right side of clipping rect to make room for the legend *par(xpd=T, mar=par()$mar+c(0,0,0,4))* # Graph autos (transposing the matrix) using heat colors, # put 10% of the space between each bar, and make labels # smaller with horizontal y-axis labels

Friends I have a data frame, df that I want to extract some rows from Here is a sample of the data > head(df) TDate Expiry Underlie Strike CSettle PSettle Futures ExDate TTE 1 20080102 200801 200803 0.840 0.0000 0 0.9207 20080104 0.005479452 2 20080102 200801 200803 0.850 0.0000 0 0.9207 20080104 0.005479452 Rate Disc 1 0.0457 0.9997496 2 0.0457

Given the following snippet.... m.nf.xts <- xts(rep(0, length(index(m.xts))), order.by=index(m.xts)) Does R know to cache the index(m.xts) or is it more efficient to say... m.i <- index(m.xts) m.nf.xts <- xts(rep(0, length(m.i)), order.by=index(m.i)) ? cheers Worik [[alternative HTML version deleted]]