similar to: Identify first row of each ID within a data frame, create a variable first =1 for the first row and first=0 of all other rows

John, Thanks for enlightening us so we better understand. I won't argue with your wish to learn to do things in base R first. I started that way, myself, and found lots of the commands not particularly easy to fit into a single worldview. Many functions I read about were promptly forgotten, especially those without great documentation and not enough examples of real world usage. This is why

Dear R help folks, First my apologizes for sending several related questions to the list server. I am trying to learn how to manipulate data in R . . . and am having difficulty getting my program to work. I greatly appreciate the help and support list member give! I am trying to write a program that will run through a data frame organized by ID and for the first line of each new group of data

Rui: "f these two, diff is faster. But of all the solutions posted so far, Ben Bolker's is the fastest." But the explicit version of diff is still considerably faster: > D <- c(rep(1,10),rep(2,6),rep(3,2)) > microbenchmark(c(1L,diff(D)), times = 1000L) Unit: microseconds expr min lq mean median uq max neval c(1L, diff(D)) 3.075 3.198 3.34396

?s 16:30 de 27/11/2024, Sorkin, John escreveu: > I am an old, long time SAS programmer. I need to produce R code that processes a dataframe in a manner that is equivalent to that produced by using a by statement in SAS and an if first.day statement and a retain statement: > > I want to take data (olddata) that looks like this > ID Day > 1 1 > 1 1 > 1 2 > 1 2 > 1 3 >

On 11/27/24 08:30, Sorkin, John wrote: > I am an old, long time SAS programmer. I need to produce R code that processes a dataframe in a manner that is equivalent to that produced by using a by statement in SAS and an if first.day statement and a retain statement: > > I want to take data (olddata) that looks like this > ID Day > 1 1 > 1 1 > 1 2 > 1 2 > 1 3 > 1 3 >

Was wondering when this would be suggested. But the question was about getting the final dataframe... newdta <- olddta newdta$FirstDay <- ave(newdata$date, newdata$ID, FUN = \(x) x[1L]) On November 27, 2024 11:13:49 AM PST, Rui Barradas <ruipbarradas at sapo.pt> wrote: >?s 16:30 de 27/11/2024, Sorkin, John escreveu: >> I am an old, long time SAS programmer. I need to

Hello! I have a data frame with dates. I need to create a new "month" that starts on the 20th of each month - because I'll need to aggregate my data later by that "shifted" month. I wrote the code below and it works. However, I was wondering if there is some ready-made function in some package - that makes it easier/more elegant? Thanks a lot! # Example data:

Check out the dplyr package, specifically the mutate function. # Create new column based on existing column value df <- df %>% mutate(FirstDay = if(ID = 2, 5)) df Repeat as needed to capture all of the day/firstday combinations you want to account for. Like everything else in R, there are probably at least a dozen other ways to do this, between base R and all of the library packages

I am an old, long time SAS programmer. I need to produce R code that processes a dataframe in a manner that is equivalent to that produced by using a by statement in SAS and an if first.day statement and a retain statement: I want to take data (olddata) that looks like this ID Day 1 1 1 1 1 2 1 2 1 3 1 3 1 4 1 4 1 5 1 5 2 5 2 5 2 5 2 6 2 6 2 6 3 10 3 10 and make it look like this: (withing each

Hi - I am trying to find and describe missing data in a time series. For instance, in the library openair, there is a data frame called "mydata": library(openair) head(mydata) date ws wd nox no2 o3 pm10 so2 co pm25 1 1998-01-01 00:00:00 0.60 280 285 39 1 29 4.7225 3.3725 NA 2 1998-01-01 01:00:00 2.16 230 NA NA NA 37 NA NA NA 3 1998-01-01 02:00:00

I am trying to use the cca/rda/capscale functions in vegan to analyse genetic distance data ( provided as a dist object calculated using dist.genpop in package adegenet) with geographic distance partialled out ( provided as a distance object using dist function in veganthis method is attempting to follow the method used by Geffen et al 2004 as suggested by Legendre and . FORTIN (2010). I

Hi Kostas, The function vectorField in the plotrix package may do what you want. See the example. Jim On Tue, Jul 25, 2023 at 9:30?PM konstantinos christodoulou <konstantinos.christodoulou1 at gmail.com> wrote: > > Dear Rcommunity, > > I hope this email finds you well. I am writing to seek your assistance with > a data visualization problem I am facing while working with R.

Dear Rcommunity, I hope this email finds you well. I am writing to seek your assistance with a data visualization problem I am facing while working with R. Problem Description: I have a dataframe named "df" containing the following columns: "longitude", "latitude", "sea_currents_mag", and "sea_currents_direction". The dataframe includes sea

Hi, I have a set of locations defined by longitude and latitude (in degrees), and want to calculate the spatial (or geographic) distance among all locations. I did not find such a function in the spatial-related packages. (I *cannot* use 'dist', as I have geographic, not cartesian coordinates). thanks! Robert Robert Ptacnik Norwegian Institute for Water Research (NIVA) Gaustadall?en 21

Hello I'm trying to render in 3D what I usually plot by image(), or image.plot() from the library fields, followed by a map("world",add=TRUE) type of command. More concretely, I have a field of temperature values, for a given geographic area, and I would like to plot a 3D surface whose x and y axes consist of longitude and latitude values and whose height and color-coding correspond

Hi all -- I am working on 64-bit Windows XP. I'm not a very technical person when it comes to the command line stuff, so please forgive me if this is a stupid question. I have a bunch of HDF files, and I want to dump a single PM25 data layer from each file to .txt by invoking ncdump.exe from system(). Here's a sample command string: "C:/ncdump -v PM25 C:/01aug2010.hdf >

Hi, This is my code (my data is attached): library(languageR) library(rms) library(party) OLDDATA <- read.csv("/Users/Abigail/Documents/OldData250412.csv") OLDDATA$YD <- factor(OLDDATA$YD, label=c("Yes", "No"))? OLDDATA$ND <- factor(OLDDATA$ND, label=c("Yes", "No"))? attach(OLDDATA) defaults <- cbind(YD, ND) set.seed(47) data.controls

Hi Everyone, I am a graduate student who will be using R to do my analysis. I need to do a spatial analysis, and the first step is to calculate the geographic distance between my study sites. I am hoping to use earth.dist because it allows for multiple pairwise distances to be calculated at one time. I have done a sample calculation, and I seem to have a problem between the steps of using

My data frame shows changes on the variable act which records the consecutive duration (in seconds) of two states (wet-dry) over a few days for several?individuals (identified by Ring). Since I want to work with daytime (i.e. from dawn till dusk) and night time (i.e. from dusk till next dawn), I have to split act in two: from time[i] till dusk and from dusk until time[i+1], and from time[k] till

Isn't anything in a data frame that is not explicitly numeric a *factor*? -Greg > -----Original Message----- > From: Peter Dalgaard BSA [mailto:p.dalgaard@biostat.ku.dk] > Sent: Friday, December 07, 2001 5:32 PM > To: Erich Neuwirth > Cc: r-devel@stat.math.ethz.ch > Subject: Re: [Rd] question > > > Erich Neuwirth