Answer by nisetama for Append an object to a list in R in amortized constant...
I ran the following benchmark:bench=function(...,n=1,r=3){ a=match.call(expand.dots=F)$... t=matrix(ncol=length(a),nrow=n) for(i in 1:length(a))for(j in...
View ArticleAnswer by WestCoastProjects for Append an object to a list in R in amortized...
For validation I ran the benchmark code provided by @Cron. There is one major difference (in addition to running faster on the newer i7 processor): the by_index now performs nearly as well as the...
View ArticleAnswer by skan for Append an object to a list in R in amortized constant...
There is also list.append from the rlist (link to the documentation)require(rlist)LL <- list(a="Tom", b="Dick")list.append(LL,d="Pam",f=c("Joe","Ann"))It's very simple and efficient.
View ArticleAnswer by xappppp for Append an object to a list in R in amortized constant...
This is a very interesting question and I hope my thought below could contribute an way of solution to it. This method do give a flat list without indexing, but it does have list and unlist to avoid...
View ArticleAnswer by JanKanis for Append an object to a list in R in amortized constant...
In the other answers, only the list approach results in O(1) appends, but it results in a deeply nested list structure, and not a plain single list. I have used the below datastructures, they supports...
View ArticleAnswer by phonetagger for Append an object to a list in R in amortized...
The OP (in the April 2012 updated revision of the question) is interested in knowing if there's a way to add to a list in amortized constant time, such as can be done, for example, with a...
View ArticleAnswer by Cron Merdek for Append an object to a list in R in amortized...
I have made a small comparison of methods mentioned here.n = 1e+4library(microbenchmark)### Using environment as a containerlPtrAppend <- function(lstptr, lab, obj)...
View ArticleAnswer by David Bellot for Append an object to a list in R in amortized...
in fact there is a subtelty with the c() function. If you do:x <- list()x <- c(x,2)x = c(x,"foo")you will obtain as expected:[[1]][1][[2]][1] "foo"but if you add a matrix with x <- c(x,...
View ArticleAnswer by Michele for Append an object to a list in R in amortized constant...
try this function lappendlappend <- function (lst, ...){ lst <- c(lst, list(...)) return(lst)}and other suggestions from this page Add named vector to a listBye.
View ArticleAnswer by Arseny for Append an object to a list in R in amortized constant...
In the Lisp we did it this way:> l <- c(1)> l <- c(2, l)> l <- c(3, l)> l <- rev(l)> l[1] 1 2 3though it was 'cons', not just 'c'. If you need to start with an empy list, use...
View ArticleAnswer by DavidM for Append an object to a list in R in amortized constant...
I think what you want to do is actually pass by reference (pointer) to the function-- create a new environment (which are passed by reference to functions) with the list added to...
View ArticleAnswer by Soo Lee for Append an object to a list in R in amortized constant...
> LL<-list(1:4)> LL[[1]][1] 1 2 3 4> LL<-list(c(unlist(LL),5:9))> LL[[1]] [1] 1 2 3 4 5 6 7 8 9
View ArticleAnswer by Paul for Append an object to a list in R in amortized constant...
Not sure why you don't think your first method won't work. You have a bug in the lappend function: length(list) should be length(lst). This works fine and returns a list with the appended obj.
View ArticleAnswer by Ken Williams for Append an object to a list in R in amortized...
You want something like this maybe?> push <- function(l, x) { lst <- get(l, parent.frame()) lst[length(lst)+1] <- x assign(l, lst, envir=parent.frame()) }> a <- list(1,2)>...
View ArticleAnswer by ayman for Append an object to a list in R in amortized constant...
If you pass in the list variable as a quoted string, you can reach it from within the function like:push <- function(l, x) { assign(l, append(eval(as.name(l)), x), envir=parent.frame())}so:> a...
View ArticleAnswer by Dirk is no longer here for Append an object to a list in R in...
If it's a list of string, just use the c() function :R> LL <- list(a="tom", b="dick")R> c(LL, c="harry")$a[1] "tom"$b[1] "dick"$c[1] "harry"R> class(LL)[1] "list"R> That works on vectors...
View ArticleAnswer by doug for Append an object to a list in R in amortized constant...
This is a straightforward way to add items to an R List:# create an empty list:small_list = list()# now put some objects in it:small_list$k1 = "v1"small_list$k2 = "v2"small_list$k3 = 1:10# retrieve...
View ArticleAppend an object to a list in R in amortized constant time, O(1)?
If I have some R list mylist, you can append an item obj to it like so:mylist[[length(mylist)+1]] <- objBut surely there is some more compact way. When I was new at R, I tried writing lappend() like...
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