similar to: Extracting elements from a list

Hi; It seems to me that has probably been asked in the past. But I cannot find the track. I usually need to extract elements from a list and contruct vector from them; e.g., to create a table. Perhaps there is a way to directly extract them without looping? Simple example: > S.lst $sublist.1 $sublist.1$age [1] 24.58719 $sublist.1$weight [1] 60.82861 $sublist.2 $sublist.2$age [1] 32.39551

Hi, S4 method dispatch can be very slow. Would it be reasonable to cache the most recent dispatch, anticipating the next invocation will be on the same type? This would be very helpful in loops. fun0 <- function(x) sapply(x, paste, collapse="+") fun1 <- function(x) { paste <- selectMethod(paste, class(x[[1]])) sapply(x, paste,

For a long time I've wanted a way to conveniently extract multiple elements from a list, which [[ doesn't allow. Can anyone suggest an efficient function to do this? Wouldn't it be a sensible addition to R? For example, alist <- list() alist[[1]] <- list() alist[[1]]$name <- "first" alist[[1]]$vec <- 1:4 alist[[2]] <- list() alist[[2]]$name <-

Dear R users, I have two simple questions here, and hope someone can help me on this. Thanks in advance. 1. I have a list object lst=list(a1=matrix(rnorm(4),2,2), a2=matrix(rnorm(4),2,2),a3=matrix(rnorm(4),2,2)). Here I only use three elements for illustration, and in fact the length of lst, n, is unknown in advance. I want to define an object for each element of this lst, and the objects have

Dear all, I think that my question is very simple but I failed to solve it. I have a list which elements are matrices like this: >mylist [[1]] [,1] [,2] [,3] [1,] 1 3 5 [2,] 2 4 6 [[2]] [,1] [,2] [,3] [1,] 7 9 11 [2,] 8 10 12 I'd like to create a matrix M<-mylist[[1]]+mylist[[2]] [,1] [,2] [,3] [1,] 8 12 16 [2,] 10 14 18

Hi,   it seems a simple problem, but I can not find a clear way. I have a list: lst=list(m=c('a','b','c'),n=c('c','a'),l=c('a','bc')) > lst $m [1] "a" "b" "c" $n [1] "c" "a" $l [1] "a"  "bc" how can I get list elements that include a given subset? for example, for given

I have a very long list that I'd like to subset based on a logical value within each element. Example below. I'd like to get just those list elements for further study whose $sig.cor slot is TRUE. In this example, I'd only want element [[2]]. Should be simple, I know. How can I do this? Thanks, Mark > gene.pair.tf.lst [[1]] [[1]]$gene.pair [1] "Lgals1:Pxmp2"

I have a "list" of character vectors. I'm trying to see if there is a way (in a single line, without a loop) to pull out the first element of all the vectors contained in the list. listOfVectors[1:length(listOfVectors][1] doesn't work. ========================== If you want more details.. Here is my listOfVectors which is called "uuu" >

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Dear all, A few months ago, I asked for your help on the following problem: I have a list with three (named) numeric vectors: > lst = list(a=c(A=1,B=8) , b=c(A=2,B=3,C=0), c=c(B=2,D=0) ) > lst $a A B 1 8 $b A B C 2 3 0 $c B D 2 0 Now, I'd love to use this list to create the following data frame: > dtf = data.frame(a=c(A=1,B=8,C=NA,D=NA), +

Dear People, Here is something I do not understand. Consider ************************************************* foo.cc ************************************************* #include <iostream> #include <R.h> #include <Rinternals.h> using std::cout; using std::endl; extern "C" { SEXP printlst(SEXP lst); } SEXP printlst(SEXP lst) { for(int i=0; i<length(lst);

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Hello,   I could not find a clear solution for the follow question. please allow me to ask. thanks   mynames=cbind(c('a','b'),c(11,22)) lst=list(a=c(1,2), b=5) now I try to combine mynames and lst: a  1  11   a  2  11 b  5  22   thanks jian   [[alternative HTML version deleted]]

Hi I have a list which cosists out of dataframes of the same structure. Now I want to extract one column (let's say column "A") from all dataframes and have them in a matrix (or dataframe). At the moment I am doiong: d <- data.frame(A=runif(100), B=rnorm(100)) theList <- list(e1=d, e2=d, e3=d, e4=d) f <- sapply(theList, function(l){l$A} ) But I am sure ther is a more

Hi, If I have a vector: junk <- c(2,0,0,3,0) and want to access, say, all the elements that are greater than zero. I just do: junk[which(junk>0)] Now, If I have a list: jlist <- list(NULL,c(1,0),NULL,c(1,2,3), NULL) and want to access all the elements that have length greater than zero, I know how to find the elements with: which(sapply(jlist,length)>0) But how do I get a

Dear R users,I have a list of equally structured lists, how can I access e.g. all 2nd compontents in those sub-lists?An example:lst <- list(rep(list(1:3),3), rep(list(4:6),3))> lst[[1]][[1]][[1]][1] 1 2 3[[1]][[2]][1] 1 2 3[[1]][[3]][1] 1 2 3[[2]][[2]][[1]][1] 4 5 6[[2]][[2]][1] 4 5 6[[2]][[3]][1] 4 5 6What I want to get are all second sub-lists, in this case:[[1]][[2]][1] 1 2

Hi everyone, I try to add many vectors (L1,L2,L3....) to many list objects (a.list, b.list....) in a workspace. Somethings like below, but it is not working. Any suggestions will be appreciated. Best, John lf=ls(pattern=".lst")  for (x in listfiles) {     dat=read.delim(x,header=F)     for (i in 1: lf) {     assign(i$add,as.numeric(dat[,3]))   #or i$add=as.numeric(dat[,3]    

Dear everyone, I am new in R and I've got difficulties in realizing the following tasks: -I have variables (factors) with different numbers of levels, either 1, 2 or 3. -I have a matrix containing these 204 factors and I have to correlate them by groups of 4 variables. -I have to delete the factors just having one level ( because when correlating one-level factors, the output is NA) here

I am looking for a way to create a vector which contains the second element of every vector in the list. However, not every vector has two components, so I need to generate an NA for those missing. For example, I have created the following list: lst <- list(c("a", "b"), c("c"), c("d", "e"), c("f", "g")) > lst [[1]]

I have a dataset in "long" format that looks something like this: ID TEST RESULT 1 A 17 1 A 12 1 B 15 1 C 12 2 B 8 2 B 9 Now what I would like to do is transpose it like so: ID TEST A TEST B TEST C 1 17 15 12 1 12 . . 2