similar to: Apply function to every 'nth' element of a vector

I have data that looks like this: > df1 group id 1 red A 2 red B 3 red C 4 blue D 5 blue E 6 blue F I want a list of the groups containing vectors with the ids. I am avoiding subset(), as it is only recommended for interactive use. Here's what I have so far: df1 <- data.frame(group=c("red", "red", "red", "blue",

R-helpers: Is there a simple way to extract every nth element from a very long vector? [The vector I want to sample from is an object returned by lowess(). It is so long (11,628 pairs of elements) that it is causing non-R-related memory problems elsewhere. I don't see a better way other than sampling the output returned from lowess.] Thanks in advance. Barry Cooke

Dear R users, Given this data: x <- seq(1,100,1) dx <- as.POSIXct(x*900, origin="2007-06-01 00:00:00") dfx <- data.frame(dx) Now to play around for example: subset(dfx, dx > as.POSIXct("2007-06-01 16:00:00")) Ok. Now for some reason I want to extract the datapoints between hours 10:00:00 and 14:00:00, so I thought well: subset(dfx, dx >

Hi, I would like to produce a plot with a symbol on every nth point in a time series data, like the one in the following: http://www.phon.ucl.ac.uk/home/yi/ProsodyPro/EnglishFocus.png x <- seq(-100,1000,25) plot(x,type="l") Could someone help me out with the above example? Thanks.... [[alternative HTML version deleted]]

I want to make a glm and then use predict. I have a fairly small sample (4000 cases) and I want to train on 90% and test on 10% but I want to do it in slices so I test on every 10th case and train on the others. Is there some simple way to get these elements? Stephen -- 21/10/2005 [[alternative HTML version deleted]]

Hello! I am working with signals and a plot of several signals on the same axes can get quite messy. With lines that are very fractured, distinction by only the linestyle is not very clear. If I add symbols to the plot however, there are so many symbols, that they overplot and the whole plot is unreadable once again. I am looking for advice on how to make a plot with continuous lines and symbols

Hello, I have 1-minute time series stock data and I'd like to calculate mean of every n-th candle data of m-days. result = c(mean of 1th data, mean of 2nd data, ...) mean of 1th data = (1th data of 2012-1-1 + 1th data of 2012-1-2 + 1th data of 2012-1-3) / 3 mean of 2nd data = (2nd data of 2012-1-1 + 2nd data of 2012-1-2 + 2nd data of 2012-1-3) / 3 ... Could you let me know the fastest

Curious to know if anyone's created something similar to the following, if so and you'd care to share an AGI or dialplan, much appreciated. I will be eventually write a script to answer the nTH call. (if I can't find it (why reinvent wheels). Looking to do some testing sending anywhere between 50-200 calls to a machine. I'd like a Snom/Polycom/whatever to pick up after the nTh

Hi, Is there a function in R to calculate the nth root, similar to the MATLAB function NTHROOT()? Thanks, Martin Biuw [[alternative HTML version deleted]]

Hi all, I need some guidance to get my problem fixed. I believe there is an issue with the ''nth'' patch from the patch-o-matic, which is labeled as status ''works''. I have tunnels back and forth across the internet, using ''nth'' to balance packets between different public networks (over the tunnels). I need to access some networks over two

Hi, Here i have an matrix like this, ABC PQR XYZ MNO ------ ------- ------ -------- 3 6 7 15 2 12 24 15 20 5 1 2 25 50 15 35 i need to get the "MODE" - for each column-wise "VARIANCE" - for

Hello, I have a question in regards to markov chains and transition probabilities. I am trying to figure out a way to calculate the "kth-step transition matrix" of a given matrix. Say for example I have a single step 2x2 matrix: 1 2 P= 1 .95 .05 2 .01. 99 If I were to convert this matrix to a 2-step transition probability matrix I would get:

First of all, I''d like to thank Andy Furniss for his direction and for helping me get a working example up and running. For the following set up to work, you will need a linux computer at the ISP (server), a linux computer at the client location (client), and some a public range of IP''s you plan to send down to your client. (as this configuration involves patching the linux

Dear All, I have to get the value of say 90th percentile of precipitation time series.. The series is of daily precipitation value of 96 years, I have to to get 90the percentile value of daily precipitation each year. If you know the R code or command for this please let me know. I would appreciate your early response. Thanking you, Sincerely, Ajay.

I have a multidimensional array - in this case with 4 dimensions of x,y,z and time. I'd like to take the time derivative of this matrix, i.e. perform the diff operator along dimension number 4. In Matlab, there is a simple option to specify which dimension the difference is to be taken across., but I can't see this in R. I realise I can use aperm to rotate my array so that time is in

Hello, I have a data frame with many rows, and I want to create a column with a name only at every 12th row, starting from 97 to 278. Thanks in advance!

Given the following.. Foo has_many :bars Bar has_many ::widgets Widget has_many :gadgets Gadget has_many :parts All of the following are now possible... @foo.bars @bar.widgets @part.gadget.widget.bar.foo However, I can''t just do the opposite of that last one... @foo.bars.widgets.gadgets.parts and get a full list of every Part associated with @foo. I know there''s several

I see many are not thrilled with the concise but unintuitive way it is suggested you use with the new R pipe function. I am wondering if any has created one of a family of functions that might be more intuitive if less general. Some existing pipes simply allowed you to specify where in an argument list to put the results from the earlier pipeline as in: . %>% func(first, . , last) In

how to use iproute/iptables to balance by packet OUTBOUND traffic between 2 PPP (pptp cable modem and pppoe adsl modem) links to the same ISP . also by using the fact that the ISP dosen''t filter source IP address - meaning i can use either PPP''s link assigned IP address as the source IP in the ip header.., it works for both devices.., what i want to achive is : when uploading a

I've written the function below to simulate the mean 1st through nth nearest neighbor distances for a random spatial pattern using the functions nndist() and runifpoint() from spatsat. It works, but runs relatively slowly - would appreciate suggestions on how to speed up this function. Thanks. --Dale library(spatstat) sim.nth.mdist <- function(nth,nsim) { D <- matrix(ncol=nth,