Displaying 20 results from an estimated 1000 matches similar to: "Newbie q. need some help understanding this code."
2009 Sep 14
2
Escaping . in regular expression
If I run
cvec<-c("test.f", "test.sf", "try.g","try.res", "try.f")
print(cvec)
indx<-grep('\.f',cvec,perl=TRUE)
fset<-cvec[indx]
print(fset)
I get
> cvec<-c("test.f", "test.sf", "try.g","try.res", "try.f")
> print(cvec)
[1] "test.f" "test.sf"
2009 Apr 04
1
Problem with sample()
Hi,
I'm having a problem using sample() within a function.
Basically I get an error reading:
Error in sample(v, 1, prob = h) : non-positive probability
Can anyone advise me as to the possible origin of this error?
Here is my code
#Discretised Gillespie algorithm function (From SMfSB, D.J. Wilkinson)
gillespied=function (N, T=100, dt=1, ...)
{
tt=0
n=T%/%dt
x=N$M
2008 Aug 18
2
matrix row product and cumulative product
I spent a lot of time searching and came up empty handed on the
following query. Is there an equivalent to rowSums that does product or
cumulative product and avoids use of apply or looping? I found a rowProd
in a package but it was a convenience function for apply. As part of a
likelihood calculation called from optim, I?m computing products and
cumulative products of rows of matrices with
2011 Apr 29
1
Handling of irregular time series in lineChart
Hi,
I realized that when I have irregular series to feed into lineChart,
the interval of each point in the chart does not seem to take care of
irregular time interval I specified in my input xts time series. But
rather, lineChart seems to take each point as equal spaced time
series. For example, I have the following code:
library(quantmod)
options(digits.sec=3)
t0 <-
2015 Feb 01
2
invoking R function in C++ in parallel
On Sat, Jan 31, 2015 at 7:05 PM, Dirk Eddelbuettel <edd at debian.org> wrote:
[...]
> - either work in something like OpenMP and run in multiple threads that
> remain /completely/ shielded from R, ie no R calls, and not even R data
> types as you cannot trigger gc() calls from different threads
>
I think you can use R objects, as long as you don't call R functions on
2002 Sep 03
1
t(xmat)
Hi,
I have a matrix and time series "xmat". I have no problem executing any matrix functions except t(xmat) which gives the following error message. My question if "xmat" is a matrix why I can not execute this matrix function?? converting the time series and matrix into a data frame solves the problem
>dim(xmat)
[1] 98 7
> t(xmat)
Error in "tsp<-"(*tmp*,
2009 Oct 23
1
help using R's linprog for LP
Hi,
I am using R in one of my courses. I am trying to use R's linprog
package to solve to formulate 2-class classification problem as Linear
programming problem.
For my formulation, I need to set to "cvec" to all 0s.
I know the points are linearly separable so an optimal solution "x"
does exist, which satisfies all the constraints.
But given the constraints and setting
2005 Jul 07
3
xmat[1, 2:3] <- NULL
I have a situation where I'm filling out a dataframe
from a database. Sometimes the database query doesn't
get anything, so I end up trying to place NULL in the
dataframe like below.
> temp <- NULL
> xmat <- as.data.frame(matrix(NA, 2, 3))
> xmat[1, 2:3] <- temp
Error in if (m < n * p && (n * p)%%m)
stop(gettextf("replacement has %d items, need %d",
2005 Jul 22
1
find confounder in covariates
Hi,
I was wondering if there is a way, or function in R to
find confounders. For istance,
> a = sample( c(1:3), size=10,replace=T)
> X1 = factor( c('A','B','C')[a] )
> X2 = factor( c('Aa','Bb','Cc')[a] )
> Xmat = data.frame(X1,X2,rnorm(10),rnorm(10))
> dimnames(Xmat)[[2]] = c('z1','z2','z3','y')
Now,
2010 Jul 14
1
Converting POSIXct vales to real values
I have a dataframe that contains time values in the form of yyyy-mm-dd hh:mm i.e. 2010-07-14 13:00. When I convert this to numeric via tvec <- as.numeric(Time) I get a number that is in seconds. So far so good. When I then divide the numeric value by the number of seconds in a day eg tvec/(60*60*24) I only get integer values and not fraction of a day which is what I want.
What do I need to
2009 Mar 05
3
methods package
I'm working on the next version of coxme, one step of which is converting
the bdsmatrix library from Splus to R. Actually, it is a conversion from
S4 methods as first described in the Green book to S4 methods as they
currently exist. Mostly it's going ok, but not entirely.
1. The biggest issue is lack of documentation. The online help pages have
not been a help; they keep saying
2004 Mar 03
1
match.call(), S4
I get different results from match.call(), according to whether a function
is dispatched via S3 or S4. Specifically, when I use S4 dispatch in the
following example, the match.call() result is of length 1 less than I
expect. I need to add an extra comma to get the same results as in the S3
method.
--------example
setClass("foo",representation("matrix"))
2007 Apr 13
3
apply problem
Dear R-Help
I am running apply on a data.frame containing factors and numeric
columns. It appears to convert are columns into as.character? Does it
convert data.frame into matrix? Is this expected? I wish it to recognise
numerical columns and round numbers. Can I use another function instead
of apply, or should I use a for loop in the case?
> summary(xmat)
A B
2012 Oct 27
2
Class generator functions for reference classes
As of rev. 61035 in r-devel, setRefClass() now returns a generator
function, as setClass() has done since 2.15.0.
The convenient style is now:
mEdit <- setRefClass("mEdit",......)
xx <- mEdit(data = xMat)
instead of
xx <- mEdit$new(data = xMat)
The returned object still has fields and methods accessible as before.
See the "Value" and "Reference Class
2004 Sep 28
3
sapply behavior
Hi,
I use sapply very frequently, but I have recently noticed a behavior of
sapply which I don't understand and have never seen before. Basically,
sapply returns what looks like a matrix, says it a matrix, and appears to
let me do matrix things (like transpose). But it is also a list and behaves
like a list when I subset it, not a vector (so I can't sort a row for
instance). I
2011 Aug 26
3
How to vectorize a function to handle two vectors
Dear R-users
I am trying to "vectorize" a function so that it can handle two vectors of
inputs. I want the function to use phi (a function), k[1] and t[1] for the
first price, and so on for the second, third and fourth price. I tried to do
the mapply, but I dont know how to specify to R what input I want to be
vectors (k and t)(see in the bottom what I tried). I have read the help
file,
2005 May 20
1
using src/Makevars file
Hi all,
Thanks to all who offered advice on using F95 in R.
Now I'm trying to compile a test package using gfortran, Linux 2.4.21 and
R 2.1.0.
I was able to successfully compile and use a test F95 routine by setting my
environment variables as follows in bash:
export PATH=~/bin/:$PATH
export F77=gfortran
export LD_LIBRARY_PATH=~/bin/irun/lib
export GFORTRAN_STDIN_UNIT=-1
Now I'm
2007 Apr 05
2
Likelihood returning inf values to optim(L-BFGS-B) other options?
Dear R-help list,
I am working on an optimization with R by evaluating a likelihood
function that contains lots of Gamma calculations (BGNBD: Hardie Fader
Lee 2005 Management Science). Since I am forced to implement lower
bounds for the four parameters included in the model, I chose the
optim() function mith L-BFGS-B as method. But the likelihood often
returns inf-values which L-BFGS-B
2003 Sep 26
2
checking generic/method consistency
Hi,
I wrote a package for linear programming and want to submit it to CRAN.
Since the package 'quadprog' has a function with the name 'solve.QP' to
perform Quadratic Programming, I named my (main) function 'solve.LP'.
However 'R CMD check' gives one warning:
* checking generic/method consistency ... WARNING
solve:
function(a, b, ...)
solve.LP:
2020 Oct 27
3
R for-loop to add layer to lattice plot
Hello,
I am using e1071 to run support vector machine. I would like to plot
the data with lattice and specifically show the hyperplanes created by
the system.
I can store the hyperplane as a contour in an object, and I can plot
one object at a time. Since there will be thousands of elements to
plot, I can't manually add them one by one to the plot, so I tried to
loop into them, but only the