similar to: changing character to a vector name

Hi R People: Several of you pointed out that using "tapply" on a data frame will work on the iris data frame. I'm still having a problem. The iris data frame has 150 rows, 5 variables. The first 4 are numeric, while the last is a factor, which has the Species names. I can use tapply for 1 variable at a time: >tapply(iris[,1],iris[,5],mean) setosa versicolor virginica

This is a best practices / style question. The way I use RODBC is I something like this: > foo <- sqlQuery(db, "select * from foo") > apply(foo, 1, function{...}) That is, I use apply to iterate over each result -- row -- in the RODBC-produced dataframe. Is this how one generally wants to do this? My concern is that when apply iterates over the rows, it uses as.matrix()

Dear R-help, First I apologize if my question is quite simple. I need add some of data in the first place my dataset, how can I do that. I have tried with rbind, but I did not succes. 0.1 3.6 0.4 0.9 rose 4.1 4.0 1.2 1.2 rose 4.4 3.2 1.9 0.5 rose 4.6 1.1 1.1 0.2 rose For example,

Hi there: I have a question about generating mean value of a data.frame. Take iris data for example, if I have a data.frame looking like the following: --------------------- Sepal.Length Sepal.Width Petal.Length Petal.Width Species 1 5.1 3.5 1.4 0.2 setosa 2 4.9 3.0 1.4 0.2

Hi all, I have to recode some values in a dataset. for example changing all zeros to "." or 999 would be also ok. does anybody know how to do this? thanks in advance. lars -- View this message in context: http://www.nabble.com/-R--Replacing-values-tf2841687.html#a7934402 Sent from the R help mailing list archive at Nabble.com.

Dear all What is the easy way to drop a variable by using its name (and not its number)? Example: > data(iris) > head(iris) Sepal.Length Sepal.Width Petal.Length Petal.Width Species 1 5.1 3.5 1.4 0.2 setosa 2 4.9 3.0 1.4 0.2 setosa 3 4.7 3.2 1.3 0.2 setosa 4 4.6 3.1

I was preparing an e-mail for the help list and ran across a quandary. When asking for help it is useful to include the code/data so others can run your code and test it. I was running code on a data frame and wanted to include a small version of the data frame. The data frame was based on experimental data. What is the best way to do this? I didn't want to send an attachment so a wrote code

I require some help in debugging this code  library(neuralnet) ir<-read.table(file="iris_data.txt",header=TRUE,row.names=NULL) ir1 <- data.frame(ir[1:100,2:6]) ir2 <- data.frame(ifelse(ir1$Species=="setosa",1,ifelse(ir1$Species=="versicolor",0,""))) colnames(ir2)<-("Output") ir3 <- data.frame(rbind(ir1[1:4],ir2))

I've just tried to merge 2 data sets thinking they would only keep the common columns, but noticed the column count was not adding up. I've then replicated a simple example and got the same thing happening. q1. why doesn't 'b' have a column name? q2. when I merge, why does the new column 'y' have all values as 5.1? Thanks in advance, Mr. confused > a <-

Hi, [I sent this to the plyr mailing list (late) last night, but it seems to be lost in the moderation queue, so here's a shot to the broadeR community] Apologies in advance for being more verbose than necessary, but I'm not even sure how to ask this question in the context of plyr, so ... here goes. As meaningless as this might be to do with the `iris` data, the spirit of it is what

Greetings R experts, I'm having some difficulty recovering lda objects that I've saved within sublists using the save.image() function. I am running a script that exports a variety of different information as a list, included within that list is an lda object. I then take that list and create a list of that with all the different replications I've run. Unfortunately I've been

Dear All, I'm a Marine Biologist using R (in a most informal and applied way) for a couple of years. Actually, I've been using R to analyse the results supporting my thesis. I would like to put together (in the same file) the data (.txt files) and the scripts files (.R files) for each chapter. How can I do this? Thanks in advance, Eduardo Esteves [[alternative HTML version deleted]]

Dear all I have a simple problem which I thought is easy to solve but what I tried did not work. I want to change character variables to factor in data frame. It goes easily from factor to character, but I am stuck in how to do backwards conversion. Here is an example irisf<-iris irisf[,2]<-factor(irisf[,2]) # create second factor str(irisf) 'data.frame': 150 obs. of 5

Dear all, How can I obtain the union of a list of logical values? Consider the following: x <- head(iris) x[,c(2,4)] <- NA x[c(2,4),] <- NA # > x # Sepal.Length Sepal.Width Petal.Length Petal.Width Species # 1 5.1 NA 1.4 NA setosa # 2 NA NA NA NA <NA> # 3 4.7 NA 1.3

Hopefully I will not be flamed for this on the list, but I am starting out with R and having some trouble with combining plots. I am playing with the famous iris dataset (checking out example dataset in R while reading through Introduction to datamining) What I would like to do is create three graphs (combined boxplots) besides each other for each of the three species (Setosa, Versicolour and

Dear all It is difficult to use round(..., digits=2) on a data frame since one has to first take care to remove non-numeric variables such as 'character' or 'factor': > head(round(iris, 2)) Error in Math.data.frame(list(Sepal.Length = c(5.1, 4.9, 4.7, 4.6, 5, : non-numeric variable in data frame: Species > head(round(iris[1:4], 2)) Sepal.Length Sepal.Width Petal.Length

Hi folk, I tried this and it works just perfectly tapply(iris[,1],iris[5],mean) but, how to obtain a single table from multiple variables? In tapply x is an atomic object so this code doesn't work tapply(iris[,1:4],iris[5],mean) Thanx and great summer holidays Gianandrea -- View this message in context: http://www.nabble.com/multiple-tapply-tp18868063p18868063.html Sent from the R help

I use by() to generate a summary statistics like so: Lbys <- by(dat[Nidx], dat$LipTest, summary) where Nidx is an index vector with names picking out the columns in the data frame dat. This returns a list of character arrays (see below for str() output) where the columns are named correctly but the rownames are empty strings and the values are strings prepended with the summary

Hi all, I have a three columned list that I have imported into R. The first column is a plot (ex. Plot1), the second is a species name (ex ACERRUB) and the third a numeric value. I want to replace some of the second column names with other names (for example replace ACERRUB with ACERDRU). The original and replacement values are in separate lists (not vectors), but I can't seem to find the

Hi, I was wondering if it is possible to get the rowindices without using the function "which" because I don't have a restriction criteria. Here's an example of what I mean: # take 10 randomly selected instances iris[sample(1:nrow(iris), 10),] # output Sepal.Length Sepal.Width Petal.Length Petal.Width Species 76 6.6 3.0 4.4 1.4