similar to: levels values of cut()

Dear all, Trying to extract a few rows for each element of a list of data.frames, I'm puzzled by the following behaviour, > d <- lapply(1:4, function(i) data.frame(x=rnorm(5), y=rnorm(5))) > str(d) > > lapply(d, "[", i= c(1)) # fine, this extracts the first columns > lapply(d, "[", j= c(1, 3)) # doesn't do nothing ?! > > library(plyr)

Dear all, Trying to extract a few rows for each element of a list of data.frames, I'm puzzled by the following behaviour, > d <- lapply(1:4, function(i) data.frame(x=rnorm(5), y=rnorm(5))) > str(d) > > lapply(d, "[", i= c(1)) # fine, this extracts the first columns > lapply(d, "[", j= c(1, 3)) # doesn't do nothing ?! > > library(plyr)

Dear all, I'm writing a code that requires Bessel functions with complex argument. Searching the list, I found the continuation of a thread I initiated a few months ago: http://tolstoy.newcastle.edu.au/R/e4/devel/08/03/0746.html As I understand, the most promising option would be to use the fortran or C implementation of Amos,

Dear list, I have a data.frame with x, y values and a 3-level factor "group", say. I want to create a new column in this data.frame with the values of y scaled to 1 by group. Perhaps the example below describes it best: > x <- seq(0, 10, len=100) > my.df <- data.frame(x = rep(x, 3), y=c(3*sin(x), 2*cos(x), > cos(2*x)), # note how the y values have a different

Dear list, I've written a small utility function to add arbitrary legend(s) to a lattice graph (or a combination of them), much like the legend function of base graphics. I though perhaps it could be useful to someone else, or improved by suggestions. I understand this goes against the lattice paradigm somewhat, in that you short-cut the link between group variables and the

Dear list, I'm trying to use the reshape package to perform a merging operation on a list of data.frames as illustrated below, > a <- 1:10 > example <- list( data.frame(a=a, b=sin(a)), data.frame(a=a, > b=cos(a)) ) > > melt(example, id = a) this produces the desired result, where the data.frames have been coerced into one with a common identifier variable

Dear list, I'm having second thoughts after solving a very trivial problem: I want to extend the relevel() function to reorder an arbitrary number of levels of a factor in one go. I could not find a trivial way of using the code obtained by getS3method("relevel","factor"). Instead, I thought of solving the problem in a recursive manner (possibly after reading

DeaR list, I happily use eigen() to compute the eigenvalues and eigenvectors of a fairly large matrix (200x200, say), but it seems over-killed as its rank is limited to typically 2 or 3. I sort of remember being taught that numerical techniques can find iteratively decreasing eigenvalues and corresponding orthogonal eigenvectors, which would provide a nice alternative (once I have the

Dear R list, I'm having difficulties in choosing between a list or a data.frame, or an array for the storage and manipulation of my data (example follows). I've been using the three for different purposes but I would rather like to know which is more adapted to what task. Here is the data I'm currently working on: 200 observations, each observation being a vector of length

Dear R helpers, I'm trying to write a numerical scheme for a boundary integral method to solve an electromagnetic problem. This requires the computation of the distance between points at the surface of an object (a sphere, in my example). Here is my code, > require(rgl) > r<-1 > size<-10 > theta<-seq(0,2*pi,length=size*2) > phi<-seq(0,pi,length=size) > pc

Hi, I have two small issues with my R code, no big deal but curiosity really. Here is a sample code, > > x <- rnorm(1:10) > > foo <- function(a = 1, b = list(x = c(1:10), y = c(1:10))){ > > for (ii in seq(along=b$y)){ > > print(x[ii] + b$x[ii]) > } > > > } > > foo() # default OK > > foo(b=list(x=1, y=c(1:10))) # only the first

Dear all, The following example code produces a graph with ggplot2, to which I add several vertical lines of arbitrary colors. I am not satisfied with the legend: it automatically adds some vertical lines which I'd rather not see (they confuse the reader rather than add information in this case). > library(ggplot2) > dfr <- data.frame(values = sin(1:50/10), > fact =

Hello R list, I have two matrices of identical dimensions, and I want to fit a straight line for each pair of columns and plot the resulting lines. I got it to work with a for loop, but there must be a better way, > n<-5 > N<-10 > > data.x<-matrix(1:(n*N),ncol=n) > data.y<-matrix(1:(n*N) + rnorm(n*N,sd=1),ncol=n) > >

Dear all, I'm puzzled by the following example inspired by a recent question on R-help, cc <- textConnection("user_id website time 20 google 0930 21 yahoo 0935 20 facebook 1000 25 facebook 1015 61 google 0940") d <- read.table(cc, head=T) ; close(cc) table(d$user_id) # count the

Hi, I wonder whether there is a way to generate a polygon (a triangle in my case) with color gradient using grid.polygon() in package grid? I tried something like library(grid) grid.polygon(x=c(0, 0.5, 1), y=c(0.5, 1, 0.5), gp=gpar(col=NA, fill=colorRampPalette(c("green", "lightgray"), space="Lab")(200))) But am only

Hello I need to plot 3 graphs in a single column; the top two plots have the same title, and I would like it to be written only once, centered horizontally and spanning the two plots. Something like t +------------+ | | i | | | | t +------------+ l +------------+ | | e | | | | 1 +------------+ t

Hi, I need to create a text file in the following format, > 1 100.0 0 > 0 0 > 1 1 > 0 0 > 1 1 > # > 1 100.0 0 > 0 0 > 0 1 > 1 0 > 1 1 ... where # is part of the format and not a R comment. Each block (delimited by #) consists of a first line with three values, call it dose, and a list of (x,y) coordinates which are a matrix or data.frame, >

Dear list, This is a bit of an off-topic question, but I'm hoping to get some advice from more experienced people. I've used the website "Web of Science" to manually collect publication counts responding to several keywords as a function of date, since the 1960s. http://apps.isiknowledge.com/RAMore.do?product=UA&search_mode=&SID=P1g9lFJp9 at

Hi, I've started my own (first) package, part of which consists in listing common physical constants (Planck's constant, the speed of light in vacuum, etc). I'm wondering what would be a good way of dealing with pairs of value/unit. > constants <- list( cel = 2.99792458e8 , #m/s > Z0 = 376.730313461, #ohm > eps0 = 8.854187817e-12,#F/m > mu0 = 4*pi*1e-7,#N/A^2

Dear list, I've had this problem for a while and I'm looking for a more general and robust technique than I've been able to imagine myself. I need to find N (typically N= 3 to 5) zeros in a function that is not a polynomial in a specified interval. The code below illustrates this, by creating a noisy curve with three peaks of different position, magnitude, width and