Displaying 20 results from an estimated 311 matches for "7043478".
2010 Nov 09
3
Row-wise recurive function call
Dear Group,
I have a following dataset:
> a
A B C D
1 22 3 31 40
2 26 31 36 32
3 3 7 49 16
4 24 40 27 26
5 20 45 47 0
6 34 43 11 18
7 48 48 24 2
8 3 16 39 48
9 20 49 7 21
10 17 36 47 10
> dput(a)
structure(list(A = c(22L, 26L, 3L, 24L, 20L, 34L, 48L, 3L, 20L,
17L), B = c(3L, 31L, 7L, 40L, 45L, 43L, 48L, 16L, 49L, 36L),
C = c(31L, 36L, 49L, 27L, 47L, 11L, 24L,
2012 Apr 20
3
Matrix multiplication by multple constants
Dear R helpers
Suppose
x <- c(1:3)
y <- matrix(1:12, ncol = 3, nrow = 4)
> y
[,1] [,2] [,3]
[1,] 1 5 9
[2,] 2 6 10
[3,] 3 7 11
[4,] 4 8 12
I wish to multiply 1st column of y by first element of x i.e. 1, 2nd column of y by 2nd element of x i.e. 2 an so on. Thus the resultant matrix should be like
> z
[,1] [,2] [,3]
[1,] 1
2009 Feb 17
2
Efficient matrix computations
Hi,
I am looking for two ways to speed up my computations:
1. Is there a function that efficiently computes the 'sandwich product' of
three matrices, say, ZPZ'
2. Is there a function that efficiently computes the determinant of a
positive definite symmetric matrix?
Thanks,
S.A.
[[alternative HTML version deleted]]
2008 Sep 17
5
Loop on vector name
[My previous message rejected, therefore I am sending same one with some modification]
I have 3 vectors with object name : dat1, dat2, dat3
Now I want to create a loop, like :
for (i in 1:3)
{
cat(sd(dati))
}
How I can do this in R?
Regards,
2010 Nov 07
3
regular exprs
...d grep() using a suitable regular
expression, but I haven't managed to succeed.
Thanks in advance.
Best,
Dimitris
--
Dimitris Rizopoulos
Assistant Professor
Department of Biostatistics
Erasmus University Medical Center
Address: PO Box 2040, 3000 CA Rotterdam, the Netherlands
Tel: +31/(0)10/7043478
Fax: +31/(0)10/7043014
Web: http://www.erasmusmc.nl/biostatistiek/
2010 Jul 26
2
Concatenate a mix of numbers and letters to create a vector name
Dear all,
I am trying to create a vector name, for example tmax.195012 from tmax., 1950 and 12. Obviously I don't wish to simply type it because the 3 name components are changing in each iteration within a loop. Is there any way of concatenating those 3 components (which are a mixture of numbers and letters)?
Thanks for reading,
Panos
2011 Aug 23
4
Correlation discrepancy
Dear R list, I have one very elementary question regrading correlation between two variables.
x = c(44,46,46,47,45,43,45,44)
y = c(44,43,41,41,46,48,44,43)
> cov(x, y)
[1] -2.428571
However, if I try to calculate the covariance using the formula as
covariance = sum((x-mean(x))*(y-mean(y)))/8 # no of of paired obs. = 8
or
covariance = sum(x*y)/8-(mean(x)*mean(y))
gives
2010 Sep 06
3
Aggregate certain rows in a matrix
Hi,
I have a matrix that looks like this
a <- c(1,1,1,1,2,2,3,3,3,3)
b <- c(2,2,2,3,4,4,4,5,5,6)
c <- c(1,2,3,4,5,6,7,8,9,10)
M <- matrix(nr=10,nc=3)
M[,1] <- a
M[,2] <- b
M[,3] <- c
> M
[,1] [,2] [,3]
[1,] 1 2 1
[2,] 1 2 2
[3,] 1 2 3
[4,] 1 3 4
[5,] 2 4 5
[6,] 2 4 6
[7,] 3 4 7
2010 Mar 09
3
Removing Zeros from matrix
Hi Everybody,
I have a matrix of about 45 columns. Some of the rows contain zeros. Using
>data1<-data[complete.cases(data),], I can remove the "NA" rows. But I am
unable to tackle that of zeros.
Can anybody give me an idea of how to remove rows containing zeros in a
matrix.
Thanks so much
Best
Ogbos
[[alternative HTML version deleted]]
2008 Oct 14
4
request: How to ignore columns having zero sums
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
2009 Jun 08
5
mean
Hi,
I have gote the following data
x1 <- c(rep(1,6),rep(4,7),rep(6,10))
x2 <- rnorm(length(x1),6,1)
data <- data.frame(x1,x2)
and I would like to compute the mean of the x2 for each individual of x1, i. e. x1=1,4 and 6?
Thank you very much in advance,
Amori
[[alternative HTML version deleted]]
2012 Nov 01
3
convert list without same component length to matrix
Hi,
I have this lame question. I want to convert a list (each with varies in
length) to matrix with same row length by eliminating vectors outside the
needed range.
For example:
l<-list(NULL)
l[[1]]=1,2,3.7
l[[2]]=3,4,5,6,3
l[[3]]=4,2,5,7
l[[4]]=2,4,6,3,2
l[[5]]=3,5,7,2
#so say I want to only have 4 rows and 5 column in my matrix (or
data.frame) and eliminating the 5th index value in l[[2]]
2010 Oct 15
4
split data with missing data condition
Dear all
I have data like this:
x y
[1,] 59.74889 3.1317081
[2,] 38.77629 1.7102589
[3,] NA 2.2312962
[4,] 32.35268 1.3889621
[5,] 74.01394 1.5361227
[6,] 34.82584 1.1665412
[7,] 42.72262 2.7870875
[8,] 70.54999 3.3917257
[9,] 59.37573 2.6763249
[10,] 68.87422 1.9697770
[11,] 19.00898 2.0584415
[12,] 60.27915 2.5365194
[13,] 50.76850
2010 Feb 15
2
creating functions question
Hi All,
I am interested in creating a function that will take x number of lm
objects and automate the comparison of each model (using anova). Here
is a simple example (the actual function will involve more than what
Im presenting but is irrelevant for the example):
# sample data:
id<-rep(1:20)
n<-c(10,20,13,22,28,12,12,36,19,12,36,75,33,121,37,14,40,16,14,20)
2009 Feb 12
3
get top 50 correlated item from a correlation matrix for each item
Hi,
I have a correlation matrix of about 3000 items, i.e., a 3000*3000
matrix. For each of the 3000 items, I want to get the top 50 items that
have the highest correlation with it (excluding itself) and generate a
data frame with 3 columns like ("ID", "ID2", "cor"), where ID is those
3000 items each repeat 50 times, and ID2 is the top 50 correlated items
with ID,
2008 Dec 11
5
Extracting the name of an object into a character string
Dear List,
I am writing a function in R with the facility to store models for later
use in scoring.
It would be very useful if I could include in the name of the file
stored the name of
the model object being stored, this name being chosen by the user in the
function
call. A simple function to store the name of an object as a character
string would fit the
bill, but I have not found one. name()
2009 Jan 13
5
indexing question
Hi all,
i have a pretty easy indexing question, at least i believe so. The
main reason i post it here, is that brackets and $ are hard to google.
How do I index correctly, if i just want to display the whole dataset
conditioned on the fact that some particular column equals one.
I know i can do something like: data$somecolumn[data$particularcol
==1] . That will show all "some
2009 Mar 02
0
package ltm -- version 0.9-0
...s always, any kind of feedback (e.g., questions, suggestions,
bug-reports, etc.) is more than welcome.
Best,
Dimitris
--
Dimitris Rizopoulos
Assistant Professor
Department of Biostatistics
Erasmus University Medical Center
Address: PO Box 2040, 3000 CA Rotterdam, the Netherlands
Tel: +31/(0)10/7043478
Fax: +31/(0)10/7043014
_______________________________________________
R-packages mailing list
R-packages at r-project.org
https://stat.ethz.ch/mailman/listinfo/r-packages
2009 Jun 19
0
package JM -- version 0.3-0
...s always, any kind of feedback (e.g., questions, suggestions,
bug-reports, etc.) is more than welcome.
Best,
Dimitris
--
Dimitris Rizopoulos
Assistant Professor
Department of Biostatistics
Erasmus University Medical Center
Address: PO Box 2040, 3000 CA Rotterdam, the Netherlands
Tel: +31/(0)10/7043478
Fax: +31/(0)10/7043014
_______________________________________________
R-packages mailing list
R-packages at r-project.org
https://stat.ethz.ch/mailman/listinfo/r-packages
2010 Mar 18
0
package JM -- version 0.6-0
...s always, any kind of feedback (e.g., questions, suggestions,
bug-reports, etc.) is more than welcome.
Best,
Dimitris
--
Dimitris Rizopoulos
Assistant Professor
Department of Biostatistics
Erasmus University Medical Center
Address: PO Box 2040, 3000 CA Rotterdam, the Netherlands
Tel: +31/(0)10/7043478
Fax: +31/(0)10/7043014
_______________________________________________
R-packages mailing list
R-packages at r-project.org
https://stat.ethz.ch/mailman/listinfo/r-packages