Displaying 20 results from an estimated 2000 matches similar to: "R and C pointers"
2012 Jun 21
2
debug R objects at C level
Dear R-devel,
I am now at a debugging phase, and would like to inspect the
(individual) values in an arbitrary R vector. It should be simple, but
after hours of reading I am simply unable to find the right
information.
A possible C code is:
?????????????????
# include <R.h>
# include <Rinternals.h>
# include <R_ext/Rdynload.h>
SEXP foo(SEXP x) // where x is a vector passed by
2011 Mar 30
4
a for loop to lapply
Dear all,
I am trying to learn lapply.
I would like, as a test case, to try the lapply alternative for the
Shadowlist<-array(data=NA,dim=c(dimx,dimy,dimmaps))
for (i in c(1:dimx)){
Shadowlist[,,i]<-i
}
---so I wrote the following---
returni <-function(i,ShadowMatrix) {ShadowMatrix<-i}
lapply(seq(1:dimx),Shadowlist[,,seq(1:dimx)],returni)
So far I do not get same results
2007 Jan 09
5
a question of substitute
Hi all,
I want to write a wrapper for an analysis of variance and I face a curious
problem. Here are two different wrappers:
fun.1 <- function(formula) {
summary(aov(formula))
}
fun.2 <- function(formula) {
oneway.test(formula)
}
values <- c(15, 8, 17, 7, 26, 12, 8, 11, 16, 9, 16,
24, 20, 19, 9, 17, 11, 8, 15, 6, 14)
group <- rep(1:3, each=7)
# While the first
2011 Apr 22
1
ggplot
Hello everyone,
I am using ggplot
to plot but I am getting the following error which I do not understand
Error: geom_text requires the following missing aesthetics: label
My code is
dimx<-256
library(ggplot2)
dev.new()
xandy<-expand.grid(seq(1:dimx),seq(1:dimy))
xx<-data.frame(xandy[[1]],xandy[[2]],Powermap=Powermap)
subsetxx<-subset(xx, xx$Powermap>threshold)
2012 Apr 05
2
"NA" vs. NA
Dear All,
I assume this is an R-devel issue, apologies if I missed something
obvious. I have a dataframe where the row names are country codes,
based on ISO 3166, something like this:
------------
"v1" "v2"
"UK" 1 2
"NA" 2 3
------------
It happens that "NA" is the country code for "Namibia", and that
creates problems on
2007 Jan 30
6
jump in sequence
Dear list,
This should be a simple one, I just cannot see it.
I need to generate a sequence of the form:
4 5 6 13 14 15 22 23 24
That is: starting with 4, make a 3 numbers sequence, jump 6, then another 3
and so on.
I can create a whole vector with:
myvec <- rep(rep(c(F, T, F), rep(3, 3)), 3)
Then see which are TRUE:
which(myvec)
[1] 4 5 6 13 14 15 22 23 24
I'd like to avoid
2014 Jun 16
1
index.search
Dear r-devel,
I am trying to automatically check if two successive versions of a
package have the same results (i.e. code not broken), by parsing the
example sections for each function against a previously tested
version.
While trying to replicate the code from example(), I am facing an
error related with te "index.search" function (line 7 in the example()
code).
This is the code I am
2009 Apr 10
4
split a character variable into several character variable by a character
Dear Mao Jianfeng,
"r-help-owner" is not the place for help, but:
r-help at r-project.org
(CC-ed here)
In any case, strsplit() does the job, i.e.:
> unlist(strsplit("BCPy01-01", "-"))
[1] "BCPy01" "01"
You can work with the whole variable, like:
splitpop <- strsplit(df1$popcode, "-")
then access the first part with
>
2006 Aug 09
3
objects and environments
Dear list,
I have two functions created in the same environment, fun1 and fun2.
fun2 is called by fun1, but fun2 should use an object which is created in fun1
fun1 <- function(x) {
ifelse(somecondition, bb <- "o", bb <- "*")
## mymatrix is created, then
myresult <- apply(mymatrix, 1, fun2)
}
fun2 <- function(idx) {
if (bb == "o) {
#
2011 Apr 27
6
Assignments inside lapply
Dear all I would like to ask you if an assignment can be done inside a lapply statement.
For example
I would like to covert a double nested for loop
for (i in c(1:dimx)){
for (j in c(1:dimy)){
Powermap[i,j] <- Pr(c(i,j),c(PRX,PRY),f)
}
}
to something like that:
ij<-expand.grid(i=seq(1:dimx),j=(1:dimy))
unlist(lapply(1:nrow(ij),function(rowId) { return
2007 Jan 21
2
multiple bases to decimal (was: comparing two matrices)
Hi again,
I was contemplating the solution using base 3:
set.seed(3)
mat2 <- matrix(sample(0:2, 15, replace=T), 5, 3)
Extracting the line numbers is simple:
bases <- c(3, 3, 3)^(2:0) # or just 3^(2:0)
colSums(apply(mat2, 1, function(x) x*bases)) + 1
[1] 7 23 25 8 1
The problem is sometimes the columns have different number of levels, as in:
mat1 <- expand.grid(0:2, 0:2,
2007 May 29
2
pie initial angle
Dear all,
I'd like to produce a simple pie chart for a customer (I know it's bad but
they insist), and I have some difficulties setting the initial angle.
For example:
pie(c(60, 40), init.angle=14)
and
pie(c(80, 20), init.angle=338)
both present the slices in the same direction, where:
pie(c(60, 40))
pie(c(80, 20))
present the slices in different directions.
I read everything I
2008 Apr 10
1
Computing time when calling C functions - why does an extra function call induce such an overhead?
Dear list,
I am a little puzzled by computing time in connection with calling C functions. With the function mysolve1 given below I solve Ax=B, where the actual matrix operation takes place in mysolve2. Doing this 5000 times takes 3.51 secs. However, if I move the actual matrix inversion part into mysolve1 (by uncommenting the two commented lines and skip the call to mysolve2) then the
2012 Jun 27
2
a problem of approach
Dear R-help list,
Part of a program I wrote seem to take a significant amount of time,
therefore I am looking for an alternative approach.
In order to explain what is does:
- the input is a sorted vector of integer numbers
- some higher numbers may be derived (using a mathematical formula)
from lower numbers, therefore they should be eliminated
- at the end, the vector should contain only
2005 Sep 09
1
measurement unit
Dear R-list,
Could anybody tell me where to find information about changing the measurement
unit from inch to centimeters?
I read the help from X11, I read R-intro and I did some searhing in the R
archives, but I couldn't find the answer.
For example, I would like to produce a plot of a certain width and height:
X11(width=10, height=5)
and I would like these to be centimeters, rather
2006 Mar 10
2
ifelse problem
Dear all,
There is something I'm missing in order to understand the following behavior:
> aa <- c("test", "name")
> ifelse(any(nchar(aa) < 3), aa[-which(nchar(aa) < 3)], aa)
[1] "test"
> any(nchar(aa) < 3)
[1] FALSE
Shouldn't the ifelse function return the whole aa vector?
Using if and else separately, I get the correct result...
>
2006 Oct 14
1
weight cases?
Dear all,
This is probably a stupid question for which I have a solution, which
unfortunately is not as straighforward as I'd like. I wonder if there's a
simple way to apply a weighting variable for the cases of a dataframe (well
I'm sure there is, I just cannot find it).
My toy example:
> my.data <- data.frame(var1=c("c", "e", "a",
2014 Feb 06
3
C headers
Dear list,
Just upgraded to MacOS Mavericks, fresh install of R 3.0.2 and trying to
install a previous version of my QCA package (the most recent one source
file, which passed the R CMD check --as-cran with R 3.0.1)
I seem to have some difficulties in the C code, apparently it doesn't find
some headers (please see below):
============
$ R CMD INSTALL --no-multiarch
2007 Dec 16
1
read.table and double quotes in strings
Dear all,
Some very wise data entry person gave me about an hour of a headache, trying
to find out why a 2000x500 dataframe won't be read into R.
After much trial and error, I pinpointed the problem to an accidentally
inserted double quote into a string variable (some comments from an open
question). This can be replicated by:
aa <- data.frame(id=1:2, var1=c("some \"
2005 Nov 21
4
attributes of a data.frame
Dear all,
I noticed that a data.frame has four attributes:
- names
- row.names
- class
- variable.labels
While one can use the first three (i.e. names(foo) or class(foo)), the fourth
one can only be used via:
attributes(foo)$variable.labels
(which is kind of a tedious thing to type)
Is it or would be possible to simply use:
variable.labels(foo)
like the first three attributes?
I tried:
varlab