similar to: Incrementing a counter in lapply

> From: Thomas Lumley >> >> On Tue, 14 Mar 2006, John McHenry wrote: >> >> > Thanks, Gabor & Thomas. >> > >> > Apologies, but I used an example that obfuscated the question that I >> > wanted to ask. >> > >> > I really wanted to know how to have extra arguments in >> functions that >> > would allow,

I need to develop a simple list manipulation. Although it seems easier to do it in matrix form, but I need it in list form. I have a matrix x <- matrix(c(12.1, 3.44, 0.1, 3, 12, 33.1, 1.1, 23), nrow=2) for list form example, the conversion is x.list <- lapply(seq_len(nrow(x)), function(i) x[i,]) ### list version calcnorm=function(a, b){ diff <- mapply("-", a, b)

Marc and many other people ( whose names escape me ) have been very helpful in explaining the use of lapply to me. In his last response, Marc explained that if tradevectors is a list of vectors of different lengths ( excuse my terminology ) then lapply(tradevectors,function(x) G[x]*B[x] ) will go through each component of the list as if it was a vector and apply the element by element

Suppose I have a nx2 matrix of data, X, the following code generate density estimation for each column and plot them denlist <- apply(X, 2, density) par(mfrow=c(1,2)) lapply(denlist, plot) Does anyone know how to change the main title of each density plot to "var 1", "var 2" by passing optional argument "main"? I've tried lapply(denlist, plot,

Dear all, List g has 2 elements > names(g) [1] "2009-10-07" "2012-02-29" and the list plot lapply(g, plot, main=names(g)) results in equal plot titles with both list names, whereas distinct titles names(g[1]) and names(g[2]) are sought. Clearly, lapply is passing 'g' in stead of consecutively passing g[1] and then g[2] to process the additional 'main'

Hi, First, thank you all for your help. Here is my problem (simplified): Say I have a list: a=list(matrix(50,nrow=5,ncol=5),matrix(25,nrow=5,ncol=5),matrix(10,nrow=5,ncol=5)) I'd like to use rbinom with a different probability for each matrix. I tried: b=c(.8,.1,.9) brep=rep(b,each=25) lapply(a,function(a) rbinom(25,a,brep)) but that doesn't work-- it just uses the first value of b

Hello guys, I have a list L1 of matrix. I have another list L2 with the same number of elements representing the row of the L matrix that I want to delete (L1[[i]][-L2[[i]],]) but I can't do this with lapply as it iterates through L1 (first argument) and not L2. Any idea? ----- Anna Lippel -- View this message in context:

I need to repeat a function many times, with differing parameters held constant across iterations. To accomplish this, I would like to create a list (or vector) of parameters, and then insert that list into the function. For example: q<-("l,a,b,s") genericfunction<-function(q){ } ###### The equivalent code would of course be genericfunction<-function(l,a,b,s){ } Any help

Hi, I have 3 lists, x, y, z and I'd like to perform a calculation over all the lists simultaneously. If it were a single list I could use lapply, but for more than one list I'm using a for loop. Is there an idiom that would let me use something like lapply, but the function specified to lappy would have access to an element from each list? (In Python, I would have used for a,b,c in

Dear R developers, Reviewing my code, I have realized that about 80% of the time in the lapply I need to access the names of the objects inside the loop. In such cases I iterate over indexes or names: lapply(names(x), ... [i]), lapply(seq_along(x), ... x[[i]] ... names(x)[i] ), or for(i in seq_along(x)) ... which is rather inconvenient. How about an argument to lapply which would specify the

Hi, When using lapply (or sapply) to loop over a list, can I somehow access the index of the list from inside the function? A trivial example: df1 <- split( x=rnorm(n=100, sd=seq(from=1, to=10, each=10)), f=letters[seq(from=1, to=10, each=10)] ) str(df1) #List of 10 # $ a: num [1:10] -0.801 0.418 1.451 -0.554 -0.578 ... # $ b: num [1:10] -2.464 0.279 4.099 -2.483 1.921 ... # $ c: num

Hi I have a list that has attributes: attributes(lis[2]) $names [1] "150096_at" I want to use those attributes in a function and then use lapply to apply that function to every element of the list, eg for simplicity's sake: my.fun <- function(x) { attributes(x) } Then l2 <- lapply(lis, my.fun) It seems that "attributes(x)" within the function is not the

I have a question regarding accessing the names of list components when applying a function with lapply. Here is an example that demonstrates what I'd like to do. I have a list like this one: mylist <- list(a=letters[1:10], b=letters[10:1], c=letters[1:3]) Now I would like to append the names of the list components to their corresponding vectors with the c() function. I thought this

useR's, I am trying to find a quick way to change some values in a list that are subject to a condition to be NA. Consider the 3x1 matrix: delta <- matrix(c(2.5,2.5,1), nrow = 1) And consider the list named v that has 3 elements > v v[[1]] [,1] [,2] [,3] [,4] [,5] [,6] [,7] [,8] [,9] [,10] [,11] [,12] [,13] [,14] [1,] 4.25 3.25 2.25 1.25 0.25 0.75 1.75 2.75 3.75 4.25

> There are other instances, such as Reduce where there is a bug > report pending that amounts to the same issue. Performing surgery on > expressions and calling eval is not good practice at the R level and > probably not a good idea at the C level either. It is worth thinking > this through carefully before a adopting a solution, which is what we > will be doing. Surgery on

I have very large csv files (up to 1GB each of ASCII text). I'd like to be able to read them directly in to R. The problem I am having is with the variable length of the data in each record. Here's a (simplified) example: $ cat foo.csv Name,Start Month,Data Foo,10,-0.5615,2.3065,0.1589,-0.3649,1.5955

Dear all, #Last week, I asked about merge x and y as list. #Now I have a dataset with list of list like: x <- list(list(matrix(1:20, 5, 4),matrix(1:20, 5, 4)), list(matrix(1:20, 5, 4),matrix(1:20, 5, 4))) y <- list(list(c(1, -1, -1, 1, 1),c(1, 1, -1, -1, -1)), list(c(1, 1, 1, 1, 1),c(1, 1, -1, 1, -1))) x y #I need merge x and y, I have tried with list.uni <-

Hello! I have noticed that mapply() drops names in R 2.3.1 as well as in r-devel. Here is a simple example: l <- list(a=1, b=2) k <- list(1) mapply(FUN="+", l, k) [1] 2 3 mapply(FUN="+", l, k, SIMPLIFY=FALSE) [[1]] [1] 2 [[2]] [1] 3 Help page does not indicate that this should happen. Argument USE.NAMES does not have any effect here as it used only in a bit special

Dear all, i have a programming problem that should be simple, though i am stuck with it. Please note that this is not a specific geonames problem, though i use it as an example - it´s just a basic problem with lapply. I use the geonames webservices with the R geonames packages which works almost smoothly. I have a vector of Zipcodes and i want to do a geonames lookup for all of them, which

Hi, I have a problem that I'm finding a bit tricky. I'm trying to use mapply and assign to generate curried functions. For example, if I have the function divide divide <- function(x, y) { x / y } And I want the end result to be functionally equivalent to: half <- function(x) divide(x, 2) third <- function(x) divide(x, 3) quarter <- function(x) divide(x, 4) But I want