similar to: Extracting only odd columns from a matrix

Displaying 20 results from an estimated 10000 matches similar to: "Extracting only odd columns from a matrix"

2011 Mar 25
4
read.xls -> rotate data.frame
Hi to all, how could I to rotate automatically a data sheet which was imported by read.xls? x1 x2 x3 .... xn y1 1 4 7 ... xn/y1 y2 2 5 8 .... xn/y2 y3 3 6 9 ....xn/y2 yn ... ... ... Xn/Yn to y1 y2 y3 .... yn x1 1 2 3 ..... Yn/x1 x2 4 5 6 .... Yn/x2 x3 7 8 9 .... Yn/x2 xn ... ... ... ..... Yn/xn Kind regards Knut
2012 Oct 10
3
Generating random geographical coordinates
Dear all, I have two coordinates vectors, say X and Y of length n. I want to generate for each couple of coordinates X1,Y1 X2,Y2 X3,Y3....Xn,Yn a random coordinate which is located in a square define as X +/- dx and Y +/- dy. I saw the runif function which can generate for just one value at a time what I want : runif(1, X - dx, X + dx) for X and runif(1, Y - dy, Y + dy) for Y. I would like
2011 Mar 04
2
Reading in and manipulating multiple data sets from the same input file
Hi, I am attempting to write code which will read in my data which is of this form: X1 Y1 X2 Y2 .... Xn Yn 0 0 0 0 0 0 1 0 1 255 1 0 2 255 2 0 2 255 3 0 3 0
2009 Dec 15
1
Help in R
Hello, Can anyone give me some suggestion in term of calculating the sum below. Is there a function in R that can help doing it faster? x1, x2, ...xn where xi can be 0 or 1. I want to calculate the following: sum{ beta[a+sum(xi), b+n-sum(xi) ]* [ (1-x1)dnorm(0,1)+x1dnorm(2,1) ]* [ (1-x2)dnorm(0,1)+x2dnorm(2,1) ]* ...* [ (1-xn)dnorm(0,1)+xndnorm(2,1) ] } The sum in the beginning is over all
2012 Feb 23
5
cor() on sets of vectors
suppose I have two sets of vectors: x1,x2,...,xN and y1,y2,...,yN. I want N correlations: cor(x1,y1), cor(x2,y2), ..., cor(xN,yN). my sets of vectors are arranged as data frames x & y (vector=column): x <- data.frame(a=rnorm(10),b=rnorm(10),c=rnorm(10)) y <- data.frame(d=rnorm(10),e=rnorm(10),f=rnorm(10)) cor(x,y) returns a _matrix_ of all pairwise correlations: cor(x,y)
2007 Mar 01
1
covariance question which has nothing to do with R
This is a covariance calculation question so nothing to do with R but maybe someone could help me anyway. Suppose, I have two random variables X and Y whose means are both known to be zero and I want to get an estimate of their covariance. I have n sample pairs (X1,Y1) (X2,Y2) . . . . . (Xn,Yn) , so that the covariance estimate is clearly 1/n *(sum from i = 1 to n of ( X_i*Y_i) ) But,
2005 Aug 03
1
filter data set unique, duplicate..
Hello First, thanks for the help for an earlier question about error handling! I have problem filtering a dataset. I'm trying to filter the data in the y columns based on the values in the x column, e.g.: x y1 y2 yn 1.0 1 NA 3 2.0 1 NA 11 2.0 2 NA NA 3.0
2003 Apr 02
8
lm with an arbitrary number of terms
Hello folks, Any ideas how to do this? data.frame is a data frame with column names "x1",...,"xn" y is a response variable of length dim(data.frame)[1] I want to write a function function(y, data.frame){ lm(y~x1+...+xn) } This would be easy if n was always the same. If n is arbitrary how could I feed the x1+...+xn terms into lm(response~terms)? Thanks Richard -- Dr.
2010 Oct 24
6
Contour Plot on a non Rectangular Grid
Dear All, I would like to plot a scalar (e.g. a temperature) on a non-rectangular domain (or even better: I would simply like to be able to draw a contour plot on an arbitrary 2D domain). I wonder if there is any tool to achieve that with R. I did some online search in particular on the list archives, found several queries similar to this one but was not able to find any conclusive answer. I
2006 Sep 22
2
"logistic" + "neg binomial" + ...
Hi Folks, I've just come across a kind of problem which leads me to wonder how to approach it in R. Basically, each a set of items is subjected to a series of "impacts" until it eventually "fails". The "force" of each impact would depend on covariates X,Y say; but as a result of preceding impacts an item would be expected to have a "cumulative
2008 Dec 29
4
Merge or combine data frames with missing columns
Hi R-experts, suppose I have a list with containing data frame elements: [[1]] (Intercept) y1 y2 y3 y4 -6.64 0.761 0.383 0.775 0.163 [[2]] (Intercept) y2 y3 -3.858 0.854 0.834 Now I want to put them into ONE dataframe like this: (Intercept) y1
2012 Apr 11
1
inference for customized regression in R?
Hi all, Are there functions in R that could help me do the following? We have a special type of regression which is called Geometric Mean Regression. We have done some search and found the following: https://stat.ethz.ch/pipermail/r-help/2011-July/285022.html The question is: how to do the statistical inference on GMR results? More specifically, we are looking for the prediction interval:
2006 Jul 28
2
subset of rows from matrix
Hi all, I have a dataframe of rownames that I would like to extract from a larger matrix to form a new matrix. I have tried to use subset, in this manner x<-subset(largematrix, rownames$names=largematrix$rownames) where largematrix is the larger matrix and rownames$names is the dataframe with the row names of the rows I want to extract from the larger matrix. Of course, I get error
2011 Aug 15
1
update() ignores object
Hi all, I'm extracting the name of the term in a regression model that dropterm specifies as the least significant one, and I'm assigning this name to an object. However, when I use update(), it ignores this object. Is there a way I can make it not ignore it? A reproducible example is below: > lm(x1~1+y1*y2+y3+y4,data=anscombe)->my.lm >
2010 Sep 26
1
compare a vector and a row of a matrix
From: xxgreat@hotmail.com To: r-help-bounces@r-project.org Subject: compare a vector and a row of a matrix Date: Sun, 26 Sep 2010 23:23:52 +0800 Hi Everyone: I am trying to compare a vector and rows of a matrix for example > xn <- c(1,2,4,4,5,5,5,6) >yn <- c(1,2,5,7,1,2,3,1) >mtrx <- cbind(xn, yn) when I tried, say, > c (1,4), the result was TRUE, TRUE.
2005 Feb 14
1
corrupt data frame: columns will be truncated or padded with NAs in: format.data.frame(x, digits = digits)
Hello! I posted on saturday mail with the same subject on r-help seeking for help in my work, but now I realized that this list is more appropriate for this. I think I found I bug. Bellow are comments and reproducible examples: # Create a data frame (tmp <- data.frame(y1=1:4, f1=factor(c("A", "B", "C", "D")))) y1 f1 1 1 A 2 2 B 3 3 C 4 4 D #
2005 Feb 14
1
corrupt data frame: columns will be truncated or padded with NAs in: format.data.frame(x, digits = digits)
Hello! I posted on saturday mail with the same subject on r-help seeking for help in my work, but now I realized that this list is more appropriate for this. I think I found I bug. Bellow are comments and reproducible examples: # Create a data frame (tmp <- data.frame(y1=1:4, f1=factor(c("A", "B", "C", "D")))) y1 f1 1 1 A 2 2 B 3 3 C 4 4 D #
2004 Apr 13
1
postscript image problem (PR#6763)
Full_Name: Jonathan Lees Version: 1.8.1 OS: GNU/Linux 2.4.20-20.8smp #1 SMP Submission from: (NULL) (152.2.75.114) I am having trouble with the postscript output of images. They have lines on them that are not supposed to be there. I have noticed this on numerous trials of printing various images. I looked at the postscript and I see that it appears to plot each individual block - so perhaps
2007 Dec 26
1
Can you recover default argument values of a function?
Hi. Maybe this is a stupid question. If so, I apologize, but here goes. Suppose I have a function f1(x,...) that calls a function f2(y1,y2,...,yn) in the following way: if x satisfies a certain condition, then I want to call f2(x,y2,...,yn); otherwise I want to use the default value of y1, if there is one. I could do something like the following: v <- ifelse ( is.null(x), f2( , y2,...,
2006 May 30
2
merging
Dear List, Given, y <- matrix(c(0,1,1,1,0,0,0,4,4), ncol = 3, byrow = TRUE) rownames(y) <- c("a","b","c") colnames(y) <- c("1","2","3") y y2 <- y[2:3, ] rownames(y2) <- c("x","z") y2 how can I stop merge(y, y2, all = TRUE, sort = FALSE) squishing the extra rows? Ideally I want the same as: rbind(y,