similar to: Column sums from a data frame (without the headers)

Does anyone know how to get a vector of column sum from a data frame? You can use colSums(), but this gives you a object of type "numeric" with the column labels in the first row, and the sums in the second row. I just want a vector of the sums, and I can't figure out a way to index the "numeric" object. Thanks!

Hi, I have a 5x731 array A, and I want to compute the sums of the columns. Currently I do: apply(A, 2, sum) But it turns out, this is slow: 70% of my CPU time is spent here, even though there are many complicated steps in my computation. Is there a faster way? Thanks, Martin

Dear friends I have an array consist of r-rows and c-columns e.g. x=c(1,1,1,1,2,2,2,2,3,3,3,3,4,4,4,4,0,0,0,0,0,0,0,0); x1=array(x, dim=c(4,6)) output is > x1 [,1] [,2] [,3] [,4] [,5] [,6] [1,] 1 2 3 4 0 0 [2,] 1 2 3 4 0 0 [3,] 1 2 3 4 0 0 [4,] 1 2 3 4 0 0 How can i ignore columns having zero sums? Help in this regard

I have a data set that I have imported (not sure if that makes a difference) and I would like to calculate the sum of only specific columns. I have tried >colSums(dataset, by=list(dataset$col5), dims=1) and I get an error of unused arguments I have also tried >aggregate(dataset, by=list(dataset$col5), sum) and I get the error that sum is not meaningful for factors. I want to only calculate

Hi, Given a test matrix, test <- matrix(c(1,2,3,NA,2,3,NA,NA,2), 3,3) A) How to compute the counts of each column (excluding the NA) i.e., 3, 2, 1 B) How to compute the counts of each column (excluding the NA) that are greater than the column means ? i.e., 1, 1, 0 I could write a for loop, but hope to use better alternative. [[alternative HTML version deleted]]

I have a data frame: > head(df) Time Temp Conc Repl Log10 1 0 -20 H 1 6.406547 2 2 -20 H 1 5.738683 3 7 -20 H 1 5.796394 4 14 -20 H 1 4.413691 5 0 4 H 1 6.406547 7 7 4 H 1 5.705433 > str(df) 'data.frame': 177 obs. of 5 variables: $ Time : Factor w/ 4 levels

I have a dataframe of 25 columns and 100,000 rows called ?testdf?. I wish to build a new dataframe, with 14 columns and 100,000 rows. I wish the new dataframe to have the ?trailing 12 column? mean. That is, I want column 1 of the new dataframe to have soemthing like: ?( mean(testdf[,1:12],na.rm=T)? What is the best way to accomplish this?

Fellow R programmers, I'd like to submit SQLDF statements with R objects as column names. For example, I want to assign "X" to "var1" (var1<-"X") and then refer to "var1" in the SQLDF statement. SQLDF needs to understand that when I reference "var1", it should look for "X" in the dataframe. This is necessary because my SQLDF

There are indeed speed advantages in using colSums etc. However the disadvantage is that the newbie doesn't always find the power inherent in the apply, sapply, tapply and mapply. For many things that I do, the speed is the least of my worries; although I take the point that using apply for means or sums in packages that are distibuted to others is not the way to go. As many of us have found

Hallo, I didn´t found any facilities for Halbergs cosinor analysis in R. This analysis is well known in the Chronobiology as the least square approximation of time series using cosine function of known period (in my case of 24hours-period). I tried to write a script but crashed... Can you give me some advices, please!? Thanks Anne Berger Institute of Zoo- and Wildlife Research, Berlin, Germany

Hi all, I am trying to look for a way to eliminate columns that sum to zero. Any help would be appreciated. Wade [[alternative HTML version deleted]]

I am just starting with R and have the following problem: given a matrix of ones and zeroes, say mdim=4 m<-matrix(round(runif(mdim^mdim)),mdim,mdim) how to construct the matrix of those rows of m, whose elements sum to 2. Contrary to the random matrix above, the actual matrix always has at least one such row. Serguei Kaniovski

Hi all, I'm trying to learn R after years of Matlab's experience. Here is an issue I couldn't solve today. Consider the following piece of code (written by memory): for(i in 1:n){ submat <- data[1:i,] C <- colSums(submat) } The problem is that at the first iteration, data[1:1,] reduces to a vector and colSums returns an error. This sounds really strange to me

Full_Name: Nick Efthymiou Version: R1.5.0 and above OS: Red Hat Linux Submission from: (NULL) (162.93.14.73) With the introduction of the functions rowSums(), colSums(), rowMeans() and colMeans() in R1.5.0, function "SEXP do_colsum(SEXP call, SEXP op, SEXP args, SEXP rho)" was added to perform the fast summations. We have an excellent opportunity to improve the accuracy by

Greetings, I am attempting to run a function, which produces a vector and requires two input variables, across two nested factor levels. I can do this using by(X, list(factor1, factor2), function), however I haven't found a simple way to extract the list output into an organized vector form. I can do this using nested loops but it isn't exactly an optimal approach. Thank you

Hi, Here i have a matrix like this, OLDMatrix <- X1 X2 X3 ----- ------ ------ 22 24 23 25 27 27 10 13 15 the thing is, im running two function(SUM,COUNT) to get output in another matrix called NEWMatrix NEWMatrix <- c("SUM",colSums(OLDMatrix )) NEWMatrix <- c("COUNT",colSums(!is.na(OLDMatrix

Hi, I have a matrix, say m=matrix(c( 983,679,134, 383,416,84, 2892,2625,570 ),nrow=3 ) i can find its row/col sum by rowSums(m) colSums(m) How do I divide each row/column by its rowSum/colSums and still return in the matrix form? (i.e. the new rowSums/colSums =1) Thanks. Casper -- View this message in context:

Hi, I am trying to aggregate the sum of my test data.frame as follow: testDF <- data.frame(v1 = c("a", "a", "a", "a", "a", "b", "b", "b", "b", "b", "c", "c", "c", "c", "c", "d", "d", "d", "d",

Hi all, I have a problem with retreaving column from a data.frame that is I have a data.frame named "temp" in that dataframe some column are there whose names are "IDENTIFIER" "UNIQUEID" "TRIALGROUPSID" "GRPNUMBER" "GRPDESC" "SEXDID" "STDID" "STUDYTYPE" "SDID"

Hi Folks, [This is not unrelated to the current "vector of vectors" thread, but arises quite independently] Say I have a function f(x,y) which computes a value for scalar x and y; or, if either x=X or y=Y is a vector, a corresponding vector of values f(X,y) or f(x,Y) (with the usual built-in vectorisation of operations). Now I have X=(x.1,x.2,...,x.m) and Y=(y.1,y.2,...,y.n). I'm