similar to: Efficient way to use data frame of indices to initialize matrix

I'm just getting started with R, so feel free to point me to the appropriate documentation if this is already answered somewhere (though I've been unable to find it myself). This does seem like a rather basic question. I want to fold a table into a matrix. The table is formatted like so: Column_Index Value 1 486 2 688 3 447 4 555 5

I'm currently using the below function from some library (MASS?) for writing my data out to file. I'm using it instead of plain old "write" because it does buffering. The problem that I'm having is that the numbers are space padded, but I need true tab-delineated files. It looks like the spaces are coming from 'format', but I don't see an option for format to

Dear all, I'd like to subset a df within a function, and use select for choosing the variable. Something like (simplified example): mydf <- data.frame(a= 0:9, b= 10:19) ttt <- function(vv) { tmpdf <- subset(mydf, select= vv) mean(tmpdf$vv) } ttt(mydf$b) But this is not the correct way. Any help? Thanks in advance Juli

Hi, I'm turning my wheels on this and keep coming around to the same wrong solution - please have a look and give a hand ... The premise is: a DF like so > loremIpsum <- "Lorem ipsum dolor sit amet, consectetur adipiscing elit. Quisque leo ipsum, ultricies scelerisque volutpat non, volutpat et nulla. Curabitur consequat ullamcorper tellus id imperdiet. Duis semper malesuada

Hi All, New to R, but committed. I looked in a number of places but can't figure out my current problem. I have date of the type: Time Type1 Type2 Type3 1 .50 .25 .25 4 .55 .25 .20 5 .65 .20 .15 etc which describe the frequency of types 1, 2 and 3 (adding up to 100%) over time. I would like to create a stacked bar chart showing these

Hi Group, I have a matrix, and I would like to replace numbers less than 0 by the smallest minimum number. Below is an small matrix, and the loop I used. I would like to get suggestions on the "R way" to do this. Thanks, Juliet # example data set mymat <- structure(c(-0.503183609420937, 0.179063475173256, 0.130473004669938, -1.80825226960127, -0.794910626384209, 1.03857280868547,

Dear R-devs, Below is a small example of what I am trying to achieve, that is trivial in R and I would like to learn how to do in C, for very large matrices: > (mymat <- matrix(c(1,0,0,2,2,1), nrow = 2)) [,1] [,2] [,3] [1,] 1 0 2 [2,] 0 2 1 And I would like to produce: [1] "a*C" "B*c" Which can be trivially done in R via something like: foo

Dear R-experts, I have found a splom-modification online which is given below. This works perfectly, but I would like to have a matrix of given correlation values to be used in the lower triangular part (lower.panel) of the splom-plot instead of calculated correlation values. Here is the matrix I would like to use (it can be any other convenient data structure):

Hi all, as I am trying to move slowly from just "working" to "good" code, I'd like to ask if there's a smarter way than using a for-loop in tasks like the example below. I need to obtain the extrema of the cumulated sum of a detrended time series. The following code is currently used, please have a look at the comments for my questions and remarks: system.time({ X

Dear all, I have about 30,000 matrix (512x512), with values from 1 to N. Each value on a matrix represent a habitat patch on my matrix (i.e. my landscape). Non-habitat are stored as ZERO. No I need to change each 1-to-N values for the same random number. Just supose my matrix is: mymat<-matrix(c(1,1,1,0,0,0,0,0,0,0,0, 0,0,0,0,2,2,2,0,0,0,0, 0,0,0,0,2,2,2,0,0,0,0, 3,3,0,0,0,0,0,0,0,4,4,

Hi everybody! I have a matrix of class "myClass", for example: myMat <- matrix(rnorm(30), nrow = 6) attr(myMat, "class") <- "myClass" class(myMat) When I extract part of ''myMat'', the corresponding class ''myClass'' unfortunately disappear: myMat.p <- myMat[,1:2] class(myMat.p) Please for any advice / suggestions, how

I noticed something surprising (in R 2.2.1 on WinXP) According to the documentation, rownames and colnames are character vectors. Assigning a vector of class POSIXct or POSIXlt as rownames or colnames therefore is not strictly according to the rules. In some cases, R performs a reasonable typecast, but in some other cases where the same typecast also would be possible, it does not. Assigning a

I noticed something surprising (in R 2.2.1 on WinXP) According to the documentation, rownames and colnames are character vectors. Assigning a vector of class POSIXct or POSIXlt as rownames or colnames therefore is not strictly according to the rules. In some cases, R performs a reasonable typecast, but in some other cases where the same typecast also would be possible, it does not. Assigning a

Hi all I was wondering whether there has ever been an update on the rownames and colnames behaviour as described by Eric below? I still get the same behaviour, exactly as described by Eric, on my WinXP installation of R-2.3.0. I also posted a message to r-help on Friday but looking through the online archives it seems to have not made it to the list. I would agree with Eric that a consistent

Is there a function in R that corresponds to the function ``map'' of perl? It could be called like: vector.a <- map( vector.b, FUN, args.for.FUN ) It should execute for each element ele.b of vector.b: FUN( vector.b, args.for.FUN) It should return a vector (or data.frame) of the results of the calls of FUN. It nearly works using: apply( data.frame( vector.b ), 1, FUN,

Hi All, I would like to make an invitation to make a collective package with all functions related to TABLES. I know that there are many packages with these functions, the original idea is collect all this functions and to make a single package, because is arduous for the user know all this functions broadcast in many packages. So, I think that the original packages can continue with its

Hello, I want to create a matrix of N random numbers with a uniform distributions. Later, I want to repeat T times each row of this matrix. For this I do the following loop: N<-45 T<-10 n<-N*T a<-matrix(runif(N,min=-1,max=1),nr=N) mymat<-matrix(rep(NA,n),nr=n,nc=1) for(i in i:N){ b<-rep(a[i,],T) mymat[i,]<-b } Mi problem is that with this loop I can see the output of the

I'm trying to find a clever way to re-map data from a database query into a data.frame. Querying a database often returns a table (data.frame) like this: GeneID MethodID Value 6 1 123 6 2 456 6 3 987 7 1 234 7 3 432 8 2 190 8 3 34 8 1 864 Note that GeneID=7 doesn't have a value for MethodID=2. Note that GeneID=8 doesn't have the

Hello, I am working on seperate the matrix to two matrices but got trouble on doing it. Please give me some suggestions on doing this. Thanks a looooooooooooot! My original matrix m is as follows for example, [,1] [,2] [,3] [1,] 6 8 1 [2,] 5 9 2 [3,] 20 10 3 [4,] 7 11 4 [5,] 8 12 5 [6,] 25 13 6 [7,] 14 14 7 I want to generate two

Dear R Gurus, As you probably know, dist calculates the distance between every two rows of data. What I am interested in is the actual two rows that have the least distance between them, rather than the numerical value of the distance itself. For example, If the minimum distance in the following sample run is d[14], which is .3826119, and the rows are 4 & 6. I need to find a generic way to