Displaying 20 results from an estimated 2000 matches similar to: "Componentwise means of a list of matrices?"
2010 Sep 01
3
standardize columns selectively within a dataframe
Dear all,
I have a dataframe:
df<-dataframe(a=c(1,2,3),b=c(4,5,6),c=c(7,8,9),d=c(10,11,12))
I want to obtain a new dataframe with columns a and b being standardized
((x-mean(x))/sd(x)); the other two columns (c,d) I want to leave
unchanged. What is the best way to achieve this? I have been trying to
use subscripts but did not succeed so far.
Any tips?
Many thanks,
Olga
2007 Oct 25
1
meaning of "trim" in mean()
(I see this in both R-patched r43124 and R-devel r43233.)
In the Argument section of ?mean:
trim the fraction (0 to 0.5) of observations to be trimmed from each
end of x before the mean is computed. Values outside that range are
taken as the nearest endpoint.
Then in the Value section:
If trim is non-zero, a symmetrically trimmed mean is computed with a
fraction of trim observations
2012 Nov 14
1
Winsorisation function
Dear all,
someone can find what I doing wrong with the following function. It is
for winsorisation mean. At my eyes it is ok, but for reason I sometimes it
is changing the results when I change the k value.
wmean <-
function (x, na.rm = FALSE, k = 1) {
if (any(i.na <- is.na(x))) {
if (na.rm)
x <- x[!i.na]
else return(NA)
}
n
2010 Oct 03
1
plyr: a*ply with functions that return matrices-- possible bug in aaply?
I have an application where I have a function to calculate results for
a 2-way table or matrix, which
returns a matrix with one less row and column. To keep this short, the
function below captures the structure:
fun2way <- function(f){
if (!length(dim(f)) ==2) stop("only for 2-way arrays")
R <- dim(f)[1]
C <- dim(f)[2]
f[1:(R-1), 1:(C-1)]
}
Now, I want to
2008 Aug 08
8
RPro
I recently came across a flyer from REvolution Computing, and I wanted to
ask if this is R going private?
Tony.
[[alternative HTML version deleted]]
2009 Jan 16
2
Winsorizing Multiple Variables
Hi All,
I want to take a matrix (or data frame) and winsorize each variable.
So I can, for example, correlate the winsorized variables.
The code below will winsorize a single vector, but when applied to
several vectors, each ends up sorted independently in ascending order
so that a given observation is no longer on the same row for each
vector.
So I need to winsorize the variable but
2009 Mar 28
2
text matching and substitution
I am trying to simplify a text variable by matching and replacing it with a
string in another vector
so for example in
colours <- paste(letters,colours(),"stuff",LETTERS)
find and replace with ("red","blue","green","gray","yellow","other") -
irrespective of case
its a large dataset, so i'd like to be able to do this
2004 Mar 05
1
Application of step to coxph using method="exact" (PR#6646)
Full_Name: John E. Kolassa
Version: Version 1.8.1
OS: Solaris
Submission from: (NULL) (128.6.76.36)
Stepwise model selection for coxph appears to fail with method="exact".
The code
step(coxph(Surv(1:100,rep(1,100))~factor(rep(1:4,25)),method="exact"))
produces the error message
Start: AIC= 733.07
Surv(1:100, rep(1, 100)) ~ factor(rep(1:4, 25))
Error in
2010 May 16
2
Problems with Asterisk and two Linksys SPA941
Hi
I have a big problems on my Asterisk systems :
I have one Asterisk Server with static IP (no nat) and
6 Linksys SPA941.
All SPA are after a router with NAT:
* SPA-1 and SPA-2 are on the same network,
we have a pat 5060 => SPA-1 and 5061=> SPA-2 on the internet router
* SPA-3,
we have a pat 5062 => SPA-3
* SPA-4,
we have a pat 5063 =>
2008 Jun 13
4
Sweave: looping over mixed R/LaTeX code
Dear guRus,
I would like to loop over a medium amount of Sweave code, including both R and LaTeX chunks. Is there any way to do so? As an illustration, can I create a .tex file like this using a loop within a .Rnw file, where the "1,2,3" comes from some iteration variable in R?
################################################
\documentclass{article}
\usepackage{Sweave}
\begin{document}
2007 May 12
1
function similar to "get" that works for both an object, and elements of an object?
#Is there a single function similar to "get" that works for both an object, and elements of an object ?
#(I want the function to be able to return objects, and/or the deeper elements of an object.)
#(i.e. elements of a dataframe and/or list)?
#e.g.
tempdf = data.frame(a=c(4,5,6) , b=c(10,11,12) )
templist= list(x=tempdf, y=c(1,2))
get('tempdf') #works as desired
2009 Jul 15
2
Substituting a user-defined function for a standard function in graphics
Dear R-help readers,
I'm trying to substitute my own version of plot.default, in order to
capture low-level graphics input for further manipulation. I seem to be
having difficulties getting the versions of functions that I intend to use
called at the right places.
Specifically, I have an object produced by survfit from the survival
package, and I want to save the values that
2008 Dec 28
1
Logistic regression with rcs() and inequality constraints?
Dear guRus,
I am doing a logistic regression using restricted cubic splines via
rcs(). However, the fitted probabilities should be nondecreasing with
increasing predictor. Example:
predictor <- seq(1,20)
y <- c(rep(0,9),rep(1,10),0)
model <- glm(y~rcs(predictor,n.knots=3),family="binomial")
print(1/(1+exp(-predict(model))))
The last expression should be a nondecreasing
2010 Aug 17
3
predict.lm, matrix in formula and newdata
Dear all,
I am stumped at what should be a painfully easy task: predicting from an lm object. A toy example would be this:
XX <- matrix(runif(8),ncol=2)
yy <- runif(4)
model <- lm(yy~XX)
XX.pred <- data.frame(matrix(runif(6),ncol=2))
colnames(XX.pred) <- c("XX1","XX2")
predict(model,newdata=XX.pred)
I would have expected the last line to give me the
2015 Mar 03
2
[R] Why does R replace all row values with NAs
Diverted from R-help :
.... as it gets into musing about new R language "primitives"
>>>>> William Dunlap <wdunlap at tibco.com>
>>>>> on Fri, 27 Feb 2015 08:04:36 -0800 writes:
> You could define functions like
> is.true <- function(x) !is.na(x) & x
> is.false <- function(x) !is.na(x) & !x
> and use
2004 Mar 10
3
converting lists got by tapply to dataframes
I have two lists:
xa <- list( X=c(1,2,3), Y=c(4,5,6), Z=c(7,8,9) )
xb <- with( barley, tapply( X=seq(1:nrow(barley)), INDEX=site
, FUN=function(z)yield[z]))
I can convert xa to a dataframe easily with:
as.data.frame(xa)
But if i try the same with xb I get:
as.data.frame(xb)
Error in as.data.frame.default(xb) :
can't coerce array into a data.frame
What
2012 Oct 10
3
How to replicate SAS by group processing in R
Hello,
I am trying to re-code all my programs from SAS into R.
In SAS I use the following code:
proc sort data=upper;
by tdate stock_symbol expire strike;
run;
data upper1;
set upper;
by tdate stock_symbol expire strike;
if first.expire then output;
rename strike=astrike;
run;
on the following data set:
tdate stock_symbol expiration strike
9/11/2012 C 9/16/2012
2007 May 16
3
more woes trying to convert a data.frame to a numerical matrix
I have the following csv file:
name,x,y,z
category,delta,gamma,epsilon
a,1,2,3
b,4,5,6
c,7,8,9
I'd like to create a numeric matrix of just the numbers in this csv dataset.
I've tried the following program:
sample.data <- read.csv("sample.csv")
numerical.data <- as.matrix(sample.data[-1,-1])
However, print(numerical.data) returns what appears to be a matrix of
2010 Jan 13
3
Operating on each row of data frame
Hi All
I have a data frame in which there are 4 columns .
Column 1 : name
Column 2-4 : values
I would like to calculate mean/Standard error of values in column 2-4 and
store them in column 5,6 respectively.
I have done the following but doesn't seem to work
mean_N_SE <-function(x)
{
name <- x[1]
vals <- c(x[2:4])
temp_mean <- mean(vals)
SE <- sqrt(var(x)/length(x))
}
2019 Apr 03
2
SAMBA 48 - Dependencies Python27 vs python36
Hello Everyone,
Good morning/afternoon/evening.
Is there any chance to have SAMBA 48 working with Python36 and its
derivatives? ( py36-dnspython-1.15.0.txz. py36-iso8601-0.1.11.txz,
py36-ply-3.11.txz, py36-setuptools-40.6.2.txz)
Currently SAMBA 48 requires python 26, but that is conflicting with
existing packages in the server that is using py36.
Any way to work around that issue?