Displaying 20 results from an estimated 1000 matches similar to: "bizarre seq() behavior?"
2012 Jan 10
2
strange Sys.Date() side effect
Any ideas what is the problem with this code?
> N <- 2; c(Sys.Date(), sprintf('N = %d', N))
[1] "2012-01-10" NA
Warning message:
In as.POSIXlt.Date(x) : NAs introduced by coercion
Best regards,
Ryszard
Ryszard Czerminski
AstraZeneca Pharmaceuticals LP
35 Gatehouse Drive
Waltham, MA 02451
USA
781-839-4304
ryszard.czerminski@astrazeneca.com
2012 Jan 12
3
strsplit() does not split on "."?
Any ideas what is wrong?
> strsplit("a.b", ".") # generates empty strings with split="."
[[1]]
[1] "" "" ""
> strsplit("a b", " ") # seems to work fine with split=" ", and other
characters...
[[1]]
[1] "a" "b"
>
> R.Version()
$platform
[1]
2010 Sep 27
1
smooth contour lines
Is there an easy way to control smoothness of the contour lines?
In the plot I am working on due to the undersampling the contour
lines I am getting are jugged, but it is clear "by eye" these should
be basically straight lines.
In maps package I found smooth.map function, but maybe there is a more
generic way
of accomplishing the same thing.
Ideally there would be an option to control
2012 Jan 25
1
Error in predict.randomForest ... subscript out of bounds with NULL name in X
RF trains fine with X, but fails on prediction
> library(randomForest)
> chirps <-
c(20,16.0,19.8,18.4,17.1,15.5,14.7,17.1,15.4,16.2,15,17.2,16,17,14.1)
> temp <-
c(88.6,71.6,93.3,84.3,80.6,75.2,69.7,82,69.4,83.3,78.6,82.6,80.6,83.5,76
.3)
> X <- cbind(1,chirps)
> rf <- randomForest(X, temp)
> yp <- predict(rf, X)
Error in predict.randomForest(rf, X) : subscript
2011 Jan 20
1
randomForest: too many elements specified?
I getting "Error in matrix(0, n, n) : too many elements specified"
while building randomForest model, which looks like memory allocation
error.
Software versions are: randomForest 4.5-25, R version 2.7.1
Dataset is big (~90K rows, ~200 columns), but this is on a big machine (
~120G RAM)
and I call randomForest like this: randomForest(x,y)
i.e. in supervised mode and not requesting
2010 Mar 22
1
sets package: converting a set to data frame?
I just started using nice package "sets"
and I wonder if there are utilities to convert (some) sets to data frame
(as in the example below)
> library(sets)
> a <- gset(elements = list(e('A', 0.1), e('B', 0.8)))
> lst <- as.list(a)
> nr <- length(lst)
> rnames <- character()
> for (i in 1:nr) rnames[i] <- lst[[i]]
> df <-
2010 Oct 22
3
how fit linear model with fixed slope?
I want to fit a linear model with fixed slope e.g. y = x + b
(instead of general: y = a*x + b)
Is it possible to do with lm()?
Regards,
Ryszard
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2010 Oct 04
2
plotmath: how to use greek symbols in expression(integral(f(tau)*dtau, 0, t))?
I would like to use greek "tau" as a symbol of variable to integrate
over in plotmath
expression(integral(f(tau)*dtau, 0,t))
but nothing seems to work. I tried d{\tau}, d\tau, etc.,
without any success
Is it possible? How can I accomplish this?
Best regards,
Ryszard
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2010 Nov 18
2
how to find near neighbors?
I am looking for an efficient way to find near neighbors...
More specifically...
I have two sets of points: A & B and I want to find
points in set B which are closer to set A than some
cutoff (or n-closest)
I will appreciate very much any pointers...
Ryszard
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2006 Nov 03
1
R CMD BATCH: unable to start device PNG
And on that note, here is a function that I use to get around it:
-----Original Message-----
From: r-help-bounces at stat.math.ethz.ch
[mailto:r-help-bounces at stat.math.ethz.ch] On Behalf Of Jeffrey Horner
Sent: Friday, November 03, 2006 10:01 AM
To: ryszard.czerminski at novartis.com
Cc: r-help at stat.math.ethz.ch
Subject: Re: [R] R CMD BATCH: unable to start device PNG
ryszard.czerminski
2003 Dec 09
2
problem with pls(x, y, ..., ncomp = 16): Error in inherit s( x, "data.frame") : subscript out of bounds
I don't know the details of pls (in the pls.pcr package, I assume), but if
you use validation="CV", that says you want to use CV to select the best
number of components. Then why would you specify ncomp as well?
Andy
> From: ryszard.czerminski at pharma.novartis.com
>
> When I try to use ncomp parameter in pls procedure I get
> following error:
>
> >
2002 Jun 20
4
how to skip NA columns ?
R-helpers!
na.omit() can be used to remove rows with NA's
but how can I remove columns ? and remember, which columns have been removed
?
I guess I can do t(na.omit(t(o))) as shown below, but this probably creates
a lot of overhead and I do not know which columns
have been removed.
Yours,
R
> o
[,1] [,2] [,3]
[1,] 1 NA 7
[2,] 2 NA 8
[3,] 3 NA 9
>
2009 Jan 20
5
Problem with subset() function?
Hi all,
Can anyone explain why the following use of
the subset() function produces a different
outcome than the use of the "[" extractor?
The subset() function as used in
density(subset(mydf, ht >= 150.0 & wt <= 150.0, select = c(age)))
appears to me from documentation to be equivalent to
density(mydf[mydf$ht >= 150.0 & mydf$wt <= 150.0, "age"])
2002 Jun 20
16
problem with predict()
Hi,
It is most probably just my R-ignorance, but I have following problem with
using predict(). I train the model using 164 cases and then I try to use
it on the data set with 35 cases, but I am getting 164 predictions ?
R-code below illustrates in more detail what I am doing.
Truly yours,
R
train = read.csv("train.csv", header = TRUE, row.names = "mol",
2004 Jan 15
2
prcomp scale error (PR#6433)
Full_Name: Ryszard Czerminski
Version: 1.8.1
OS: GNU/Linux
Submission from: (NULL) (205.181.102.120)
prcomp(..., scale = TRUE) does not work correctly:
$ uname -a
Linux 2.4.20-28.9bigmem #1 SMP Thu Dec 18 13:27:33 EST 2003 i686 i686 i386
GNU/Linux
$ gcc --version
gcc (GCC) 3.2.2 20030222 (Red Hat Linux 3.2.2-5)
> a <- matrix(rnorm(6), nrow = 3)
> sum((scale(a %*% svd(cov(a))$u, scale
2003 Nov 12
4
column extraction by name ?
I have a data frame (df) with colums x, y and z.
e.g. df <- data.frame(x = sample(4), y = sample(4), z = sample(4))
I can extract column z by: df$z or df[3]
I can also extract columns x,y by: df[1:2] or by df[-3].
Is it possible to extract x,y columns in a "symbolic" fashion i.e.
by equivalent of df[-z] (which is illegal) ???
Or alternativeley, is there an equivalent of
2003 Oct 24
5
how to remove NaN columns ?
How can I remove columns with NaN entries ?
Here is my simple example:
> data <- read.csv("test.csv")
> xdata <- data[3:length(data)]
> xs <- lapply(xdata, function(x){(x - mean(x))/sqrt(var(x))})
> x <- data.frame(xs)
> x
C D E F
1 -0.7071068 NaN -0.7071068 -0.7071068
2 0.7071068 NaN 0.7071068 0.7071068
2003 Oct 31
3
print(), cat() and simple I/O in R
I am trying to produce rather mundane output of the form e.g.
pi, e = 3.14 2.718
The closest result I achieved so far with print() is:
> print (c(pi, exp(1)), digits = 3)
[1] 3.14 2.72
> print(c("pi, e =", pi, exp(1)), digits = 3)
[1] "pi, e =" "3.14159265358979" "2.71828182845905"
I understand that c() promotes floats to strings and
2006 Apr 07
3
strange matrix behaviour: is there a matrix with one row?
Consider this:
> y <- matrix(1:8, ncol=2)
> is.matrix(y[-c(1,2),])
[1] TRUE
> is.matrix(y[-c(1,2,3),])
[1] FALSE
> is.matrix(y[-c(1,2,3,4),])
[1] TRUE
It seems like an inconsistent behaviour:
- with 2 or more rows we have a matrix
- with 1 row we do not have a matrix and
- with 0 rows we have a matrix again
I just stumbled on this behaviour, because I had a problem
with my
2004 Jun 09
4
how to initialize random seed properly ?
I want to start R processes on multiple processors from single shell
script
and I want all of them to have different random seeds.
One way of doing this is
sleep 2 # (with 'sleep 1' I am often getting the same number)
...
set.seed(unclass(Sys.time()))
Is there a simpler way without a need to sleep between invoking
different R processes ?
Ryszard