similar to: Dynamic resizing of lists, dataframes (newbie question)

Hello- Sorry, this is a bit of a noob question, but I can't seem to progress it any further. I have two dataframes which contain a series of strings which exactly match. The problem is one has more rows than the other (more cases have been added) and they have been sorted so that they are not in the same order. The smaller dataframe, though, contains in another column which has codes

I have 2 dataframes. "mydata" contains numerical data. "mybys" contains information on the "group" each row of the data is in. I wish to aggregate each column in mydata using the corresponding column in mybys. Please see the example below. What is a more elegant or "better" way to accomplish this task? Thanks! mydata =

Let'say we have a dataframe mydata with column v1. If mydata$v1 is passed to a function, is there way, then, to extract the name of the dataframe? What I now do is passing the name of the dataframe to the funcion, so passing two parameters. Maybe with mydata$v1 it is not possible, but with mydata['v1'] or mydata[,'v1'] it is? Thanks Frans ------------------- Frans Marcelissen

Dear R users, today I've got the following problem. Here you are a dataframe as example. There are some SAMPLES for which a CONCentration was recorded through TIME. The time during which the concentration was recorded is not always the same, 10 points for Sample A, 7 points for Sample B and 11 for sample C Also the initial concentration was not the same for the three samples. I would like

I am using the following command to replace all the missing values and assorted typos in a dataframe with NA: mydata[mydata>80]=NA The problem is that the first column contains values which should be more than 80, so really I want to do it just for mydata[,2:length(mydata)] I can't seem to re-write the code to fit: mydata[,2:length(mydata)>80]=NA # no error message, but doesn't

Hi, I searched for this in the mailing list, but found no results. I have a large dataframe ( dim(mydata)= 1297059 16, object.size(mydata= 145280576) ) , and I want to perform some calculations which can be done by a factor's levels, say, mydata$myfactor. So what I want is to split this dataframe into nlevels(mydata$myfactor) = 80 levels. But I must do this efficiently, that is, I

Hi, I'm using a loop to evaluate several models by taking adjacent variables from my dataframe. When i try to get predictions for new values, i get an error message about a missing variable in my new dataframe. Below is an example adapted from ?gam in mgcv package library(mgcv) set.seed(0) n<-400 sig<-2 x0 <- runif(n, 0, 1) x1 <- runif(n, 0, 1) x2 <- runif(n, 0, 1) x3 <-

I have read a large dataset into a dataframe using RODBC, the rows of data in the dataframe are (integer) timestamped and I would like to divide the original dataframe into n smaller dataframes where dataframe 1 contains all rows that had timestamps falling in the period 0-x1 minutes, dataframe 2 contains all rows that had timestamps falling between x1+1 and x2, etc.. Does anyone know how to

How do I retain "POSIXct" formatting when using apply, with FUN=max? #example: mydata <- rep(Sys.time(), 10) mydf <- data.frame(matrix(data=mydata, nrow=2, ncol=length(mydata) ) ) for(i in seq(mydf))class(mydf[[i]]) <- class(mydata) str(mydf) maxdates <- apply(mydf,2,max,na.rm=T) str(maxdates) #Why is the formattign now "chr", and not

Dear friends, I am trying to produce Contour Plot with R, but there are some NA in my data matrix. After I ran the following R script, I got the error message:"no proper `z' matrix specified". Does anybody know how to plot contour chart with R for the non-strict matrix? Thank you in advance!!!

Dear R-users, My script imports a dataset from a csv file, in which missing values are represented by ".". This importation is done into a dataframe using the read.table function with na.strings = "." Then I want to replace the NAs in the first column of the dataframe by "Missing data". I am using the following code to do so :

What is a "good" way to calculate the "moving product", for each row of a dataframe, where I wish to be able to specify the length of the moving product? Depending on my needs, I'd like to be able to specify the "length" over which to calculate the moving average (in this example, length=3). For example, if I have a dataframe with 20 rows and 6 columns, and I

I've seen how to replace the NA's in a single column with a data frame *> mydata$ncigs[is.na(mydata$ncigs)]<-0 *But this is just one column... I have thousands of columns (!) that I need to do this, and I can't figure out a way, outside of the dreaded loop, do replace all NA's in an entire data frame (all vars) without naming each var separately. Yikes. I'm racking my

Hi  I have a dataframe similar to: >Sample<-c(1,1,1,2,2,2,3,3,3) >Time<-c(1,2,3,1,2,3,1,2,3) >Mass<-c(3,3.1,3.4,4,4.3,4.4,3,3.2,3.5) >mydata<-as.data.frame(cbind(Sample,Time,Mass))   Sample Time Mass 1      1    1  3.0 2      1    2  3.1 3      1    3  3.4 4      2    1  4.0 5      2    2  4.3 6      2    3  4.4 7      3    1  3.0 8      3    2  3.2 9      3    3

Dear R-users, The following code splits a very simple dataframe into a list, each element of the list being one line of the dataframe. You will see that the split function names each element of the list by using uses the content of a and b and merging them with a "." character. Is there a way to customize this character? a<-1:10 b<-21:30 mydata<-data.frame(a,b)

There is a very nice Search Engine, with Keywords arranged by topic, that comes with R. If you are under Windows (and have Html help installed), you can find this in the Help menu, under "Html help". (The relevant file can also be found as ...\doc\html\search\SearchEngine.html.) Maybe this helps, Heinrich. > -----Urspr?ngliche Nachricht----- > Von: Neil Osborne

I would like to convert a dataframe to an array of lists, one for every record. A natural choide is apply as.list to the rows. However, as it seems, as.list() automatically converts all list elements to the same datatype. Eg: myData <- data.frame(a="foo",b=as.logical(rbinom(10,1,.5))); apply(myData,1,as.list); In this output, all boolean values have been converted to character

Hi everyone, Let me have a dataframe named ?mydata? and created as below, *> n=c(5,5,5,5) #number of trils > x1=c(2,3,1,3) ) #number of successes > x2=c(5,5,5,5) #number of successes > x3=c(0,0,0,0) #number of successes > x4=c(5,0,5,0) #number of successes > mydata=data.frame(n,x1,x2,x3,x4) > mydata* n x1 x2 x3 x4 1 5 2 5 0 5 2 5 3 5 0 0 3 5 1 5 0 5 4 5 3 5 0

Please see example code below. I have a vector ("mydata") of length 10. "mydata" can have various formats (e.g. numeric, text, POSIXct, etc) I use the matrix and data.frame functions to convert "mydata" to a dataframe ("mydf") of 2 columns and 5 rows. What is a "good" way to ensure that the format is retained when I create the

Hi, I would like to write a function which has the following syntax: myfn <- function(formula, ftime, fstatus, data) { # step 1: obtain terms in `formula' from dataframe `data' # step 2: obtain ftime from `data' # step 3: obtain fstatus from `data' # step 4: do model estimation # step 5: return results } The user would call this function as: myfn(formula=myform,