Displaying 20 results from an estimated 10000 matches similar to: "on abort error, always show call stack?"
2012 Mar 30
4
list assignment syntax?
Dear R wizards: is there a clean way to assign to elements in a list?
what I would like to do, in pseudo R+perl notation is
f <- function(a,b) list(a+b,a-b)
(c,d) <- f(1,2)
and have c be assigned 1+2 and d be assigned 1-2. right now, I use the clunky
x <- f(1,2)
c <- x[[1]]
d <- x[[2]]
rm(x)
which seems awful. is there a nicer syntax?
regards, /iaw
----
Ivo Welch
2010 Aug 30
4
different interface to by (tapply)?
dear R experts:
has someone written a function that returns the results of by() as a
data frame? ??of course, this can work only if the output of the
function that is an argument to by() is a numerical vector.
presumably, what is now names(byobject) would become a column in the
data frame, and the by object's list elements would become columns.
it's a little bit like flattening the by()
2013 Feb 07
4
Hard Stop?
is it possible to throw a stop() that is so hard that it will escape
even tryCatch?
/iaw
----
Ivo Welch (ivo.welch at gmail.com)
2011 Jul 24
2
split data frame temporary and work with only part of it?
dear R wizards: I have a large data frame, a million rows, 40
columns. In this data frame, there are some (about 100,000) rows
which I want to recompute (update), while I want to leave others just
as is. this is based on a condition that I need to compute, based on
what is in a few of the columns. what is the right R way to do this?
I could subset out the rows that I want to recompute into a
2004 Jul 07
3
fast NA elimination ?
dear R wizards: an operation I execute often is the deletion of all
observations (in a matrix or data set) that have at least one NA. (I
now need this operation for kde2d, because its internal quantile call
complains; could this be considered a buglet?) usually, my data sets
are small enough for speed not to matter, and there I do not care
whether my method is pretty inefficient (ok, I
2010 Jan 22
2
sorted reshaping?
dear R wizards:? I am wrestling with reshape.? I have a long data set
that I want to convert into a wide data set, in which rows are firms
and columns are years.
> summary(rin)
firm fyear sim1
Min. :1004.00 Min. :1964.0 Min. : -1.00000
1st Qu.:1010.00 1st Qu.:1979.0 1st Qu.: -0.14334
Median :1016.00 Median :1986.0 Median : 0.00116
Mean
2013 Feb 06
5
First R Package --- Advice?
Dear R experts---
after many years, I am planning to give in and write my first R
package. I want to combine my collection of collected useful utility
routines.
as my guide, I am planning to use Friedrich Leisch's "Creating R
Packages: A Tutorial" from Sep 2009. Is there a newer or better
tutorial? this one is 4 years old.
I also plan on one change---given that the
2011 Oct 10
5
multicore by(), like mclapply?
dear r experts---Is there a multicore equivalent of by(), just like
mclapply() is the multicore equivalent of lapply()?
if not, is there a fast way to convert a data.table into a list based
on a column that lapply and mclapply can consume?
advice appreciated...as always.
regards,
/iaw
----
Ivo Welch (ivo.welch at gmail.com)
2010 Jan 08
4
fast lm se?
dear R experts---I am using the coef() function to pick off the coefficients
from an lm() object. alas, I also need the standard errors and I need them
fast. I know I can do a "summary()" on the object and pick them off this
way, but this computes other stuff I do not need. Or, I can compute (X'
X)^(-1) s^2 myself. Has someone written a fast se() function?
incidentally, I think
2010 Jun 11
3
lm without error
this is not an important question, but I wonder why lm returns an
error, and whether this can be shut off. it would seem to me that
returning NA's would make more sense in some cases---after all, the
problem is clearly that coefficients cannot be computed.
I know that I can trap the lm.fit() error---although I have always
found this to be quite inconvenient---and this is easy if I have only
2011 Jul 08
2
manipulating "by" lists and "ave()" functions
dear R wizards---more ignorance on my part, exacerbated by too few
examples in the function documentations.
> d <- data.frame( id=rep(1:3,3), x=rnorm(9), y=rnorm(9))
Question 1: how do I work with the output of "by"? for example,
> b <- by( d, d$id, function(x) coef(lm( y ~ x, data=x ) ))
> b
d$id: 1
(Intercept) x
0.2303 0.3618
2012 May 09
2
big quasi-fixed effects OLS model
dear R experts---now I have a case where I want to estimate very large
regression models with many fixed effects---not just the mean type, but
cross-fixed effects---years, months, locations, firms. Many millions of
observations, a few thousand variables (most of these variables are
interaction fixed effects). could someone please point me to packages, if
any, that would help me estimate such
2012 May 31
2
print.data.frame to string?
dear R experts---is there a function that prints a data frame to a string?
cat() cannot handle lists, so I cannot write cat("your data frame is:\n",
df, "\n").
regards, /iaw
----
Ivo Welch (ivo.welch@gmail.com)
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2011 Jul 02
5
%dopar% parallel processing experiment
dear R experts---
I am experimenting with multicore processing, so far with pretty
disappointing results. Here is my simple example:
A <- 100000
randvalues <- abs(rnorm(A))
minfn <- function( x, i ) { log(abs(x))+x^3+i/A+randvalues[i] } ?## an
arbitrary function
ARGV <- commandArgs(trailingOnly=TRUE)
if (ARGV[1] == "do-onecore") {
?library(foreach)
?discard <-
2013 Feb 09
2
character strings with embedded commands: perl "/gee" ?
dear R experts---I am trying to replicate a perl feature. I want to be
able to embed R commands inside a character string, and have the
string be printed with the command executed. my perl equivalent is
my $a=10;
my $teststring = "the expression, $a+1, is ::$a+1::, but add one
more for ::$a+2::\n";
$teststring =~ s/::(.*?)::/$1/gee;
print $teststring;
of course, R does not use
2009 Sep 11
1
constrOptim parameters
Dear R wizards: I am playing (and struggling) with the example in the
constrOptim function. simple example. let's say I want to constrain my
variables to be within -1 and 1. I believe I want a whole lot of
constraints where ci is -1 and ui is either -1 or 1. That is, I have 2*N
constraints. Should the following work?
N=10
x= rep(1:N)
ci= rep(-1, 2*N)
ui= c(rep(1, N), rep(-1, N))
2013 Apr 04
6
categorized complete list of R commands?
every time I read the R release notes for the next release, I see many
functions that I had forgotten about and many functions that I never knew
existed to begin with. (who knew there were bibtex facilities in R?
obviously, everyone except me.)
I wonder whether there is a complete list of all R commands (incl the
standard packages) somewhere, preferably each with its one-liner AND
2009 Sep 15
2
why is nrow() so slow?
dear R wizards: here is the strange question for the day. It seems to me
that nrow() is very slow. Let me explain what I mean:
ds= data.frame( NA, x=rnorm(10000) ) ## a sample data set
> system.time( { for (i in 1:10000) NA } ) ## doing nothing takes
virtually no time
user system elapsed
0.000 0.000 0.001
## this is something that should take time; we need to add 10,000
2012 Dec 24
2
parallelized version of "by" and "ave"
Dear R experts---
Has anyone written parallel versions of "by" (i.e., mcby) and "ave"
(i.e. mcave) ? I did ask a question like this a year ago, and then
the answer was no.
for those who are googling the group for the answer to this question,
in the meantime, the poor man's version of "by" is mclapply( split(
ds, factor ), FUN )
I don't know the poor
2004 Aug 21
4
loadhistory() in .Rprofile ?
dear wizards: my .Rprofile has just one command for testing,
loadhistory("~/.Rhistory")
but this gives me an error on R startup:
Error: couldn't find function "loadhistory"
Invoking loadhistory() as the first interactive command works fine;
incidentally, I believe loadhistory() in the .Rprofile worked in
earlier or other platform R releases, too.
Is the .Rprofile