search for: mylist

Hi I have a list : mylist <- list( a = NULL, b = 1, c = 2 ) > mylist[1] $a NULL > is.null(mylist[1]) [1] FALSE > is.null(mylist$a) [1] TRUE why? I need to use mylist[1]

Hello I tried to define replacement functions for the class "mylist". When I test them in an active R session, they work -- however, when I put them into a package, they don't. Why and how to fix? make_my_list <- function( x, y ) { return(structure(list(x, y, class="mylist"))) } mylist <- make_my_list(1:4, letters[3:7]) mylist mylist[[...

I can define a list containing NULL elements: > myList <- list("aaa",NULL,TRUE) > names(myList) <- c("first","second","third") > myList $first [1] "aaa" $second NULL $third [1] TRUE > length(myList) [1] 3 However, if I assign NULL to any of the list element then such element is deleted...

...We face this problem all the time. A procedure generates a list of data frames. How to stack them together? The short answer is that the plyr package's rbind.fill method is probably the fastest method that is not prone to trouble and does not require much user caution. result <- rbind.fill(mylist) A slower alternative that also works is result <- do.call("rbind", mylist) That is always available in R and it works well enough, even though it is not quite as fast. Both of these are much faster than a loop that repeatedly applies "rbind". Truly blazing speed can be...

Hi, Try > is.null(mylist[[1]]) [1] TRUE Notice the double square brackets. From: ?`[` "The most important distinction between [, [[ and $ is that the [ can select more than one element whereas the other two select a single element." On Thu, Jun 15, 2017 at 11:33 AM, ce <zadig_1 at excite.com> wrote: >...

Hi r-users, I have a matrix B and a list of 3x3 matrices (mylist). I want to calculate the quantiles in the list using each of the value of B as probabilities. The codes I wrote are: B <- matrix (runif(12, 0, 1), 3, 4) mylist <- lapply(mylist, function(x) {matrix (rnorm(9), 3, 3)}) for (i in 1:length(B)) { quant <- lapply (mylist, quant...

How do I parse an identifier of a list component, e.g. mylist$mycomponent or mylist[[1]] ? Parse does not do the job, e.g. parse(text="mylist$mycomponent") returns an expression with just one term, instead of "mylist", "$", "mycomponent". What I need is a way to extract the list name (e.g. "mylist"), given...

Hi, I'm have a list of integer vectors and I want to perform an outer() like operation on the list. As an example, take the following list: mylist <- list(1:5,3:9,8:12) A simple example of the kind of thing I want to do is to find the sum of the shared numbers between each vector to give a result like: result <- array(c(15,12,0,12,42,17,0,17,50), dim=c(3,3)) Two for() loops is the easiest way but I wondered if there was a neater/fa...

...do.call is not the fastest, but it does appear to be the least prone to programmer error. I have been staring at ?do.call for quite a while and I have to admit that I just need some more explanations in order to interpret it. I can't really get why this does work do.call( "rbind", mylist) but it does not work to do sapply ( mylist, rbind). Anyway, here's the self contained working example that compares the speed of various approaches. If you send yet more ways to do this, I will add them on and then post the result to my Working Example collection. ## stackMerge.R ## Paul...

I find that the str function is more helpful for understanding the difference between a null list and a list containing a null list than the implicit print function call that the interpreter invokes when you enter an expression at the console. str( mylist[1] ) -- Sent from my phone. Please excuse my brevity. On June 15, 2017 8:39:47 AM PDT, Huzefa Khalil <huzefa.khalil at umich.edu> wrote: >Hi, > >Try > >> is.null(mylist[[1]]) >[1] TRUE > >Notice the double square brackets. > >From: ?`[` >"The most i...

Sorry My previous report is not detailed. In R, you will get this: > mylist <- list() > mylist[[1]] Error in mylist[[1]] : subscript out of bounds > mylist[[1]] <- c(1) Error: (list) object cannot be coerced to vector type 14 > mylist[[1]] <- c(1,2) > mylist[[1]] <- c(1) > mylist [[1]] [1] 1 I was trying to assigning c(1) to (mylist[[1]] <- c...

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 Is there a way to create M without loopi...

Hi, I'm pretty new to R. I have an object (say a list) and I I have a function that I call on various columns in that list (excuse terminology if it's wrong/ambiguous). Imagine its like this (actual values are unimportant) and called mylist: >mylist A B 1 5 2 5 3 6 4 8 5 0 I have a function: foo = function(param){ #modify list A or B values depending on whether A or B's passsd in (via 'param') param[someindex]=another_value #doesn't change value in lits$A or list$B (whichever's been...

Thank you all , very informative, never thought of doing a str( mylist[1] ) -----Original Message----- From: "Jeff Newmiller" [jdnewmil at dcn.davis.ca.us] Date: 06/15/2017 11:56 AM To: r-help at r-project.org, "Huzefa Khalil" <huzefa.khalil at umich.edu>, "ce" <zadig_1 at excite.com> Subject: Re: [R] is.null(mylist[1]) and...

No. I fixed that, the NAMESPACE file now contains: S3method("[[<-", mylist) S3method("$<-", mylist) It still does not work. I also created a print method (print.mylist) which did work out of the box, regardless of being in the NAMESPACE file or not. Could it be somehow in here (also in my NAMESPACE file): exportPattern("^[[:alpha:]]+") Or could i...

Dear R users, Let's say I have a list with components being 'm' matrices (as exemplified in the "mylist" object below). Now, I'd like to subset this list based on an index vector, which will partition each matrix 'm' in 2 sub-matrices. My questions are: 1. Is there an elegant way to have the results shown in mylist2 for an arbitrary number of matrices in mylist? 2. The column names...

Here i have a variable MyVar <- data.frame(read.csv("D:\\Doc.csv")) And now i am storing this variable name into a list. MyList <- list() MyList [length(MyList )+1]<- "MyVar" Now what is the requirement is, i need to call the variable name "MyVar" from the list "MyList " and get the data. ---------------------------------------------------------------------------------------------------...

Hi, I 'd like to match each member of a list to a target string, e.g. ------------------------------ mylist=c("MN","NY","FL") g=regexpr(mylist[1], "Those from MN:") if (g>0) { "On list" } ------------------------------ My question is: How to add an end-of-string symbol '$' to the to-match string? so that 'M' won't match. Of course...

...is made of lists of varying length. I wish to create a new vector that contains the last element of each list. So far I have used sapply to determine the length of each list, but I'm stymied at the part where I index the list to make a new vector containing only the last item of each list mylist = list(c(1,2,3),c("cat","dog"),c("x","y","z","zz")) # Create list last <- sapply(mylist,length) # Make vector with list lengths last_only <- mylist[[1:length(mylist)]][last] # Crash and burn trying to make new vector with...

...rnorm(10000), y=rnorm(10000), z=sample(c("foo1","foo2"), 10000,replace=T), year=sample(c(89:94), 10000,replace=T)) trellis.device("postscript", file="foo.eps") for(i in unique(X$year)){ temp <- X[X$year%in%i, ] xyplot(temp$x~temp$y|temp$z) } dev.off() mylist <- list() for(i in unique(X$year)){ temp <- X[X$year%in%i, ] mylist[[i]] <- xyplot(temp$x~temp$y|temp$z) } trellis.device("postscript", file="foo1.eps") mylist[[89]] mylist[[90]] mylist[[91]] mylist[[92]] mylist[[93]] mylist[[94]] dev.off() Thank you, Jean