Displaying 20 results from an estimated 20000 matches similar to: "zero index and lazy evaluation in ifelse()"
2003 Mar 05
2
reserved words documentation
I wanted a data frame component to be named "next", for example:
> m <- data.frame (matrix (0, nrow=2, ncol=2))
> names (m) <- c("prev", "next")
> m
prev next
1 0 0
2 0 0
But "next" being reserved prevents $ indexing without quotes:
> m$next
Error: syntax error
> m$"next"
[1] 0 0
Although they are mostly
2004 Mar 30
4
rank() vs SAS proc rank
SAS proc rank has ties options of high and low that would allow
producing ranks of the type found in the sports pages, e.g.,
rank (c(1,1,2,2,2,2,3)) == 1 1 3 3 3 3 7
Could R support these ties.methods?
2006 Jun 04
2
evaluation of the alternative expression in ifelse
Dear all,
I am trying to avoid the warnings produced by:
> x <- -2:2
> log(x)
[1] NaN NaN -Inf 0.0000000 0.6931472
Warning message:
production de NaN in: log(x)
I thought that using ifelse would be a solution, but it is not the case:
> ifelse(test = x < 0, yes = NaN, no = log(x))
[1] NaN NaN -Inf 0.0000000 0.6931472
Warning message:
production
2006 Sep 11
5
Successive Graphs
Hello! I have written an R script on a Windows platform where I
calculate eight result matrices I plot using matplot. I would like to
display the resulting plots successively, rather than simultaneously,
and I was wondering if anyone could point me in the right direction as
to how to do this. The graphs pop up in this manner by default when I
run my script in S-PLUS, with tabs separating them so I
2004 Feb 06
3
column names in matrix vs. data frame in R 1.8
Is the difference in behavior below, introduced in 1.8, inconsistent or,
at least, undesirable? I couldn't find this in the NEWS.
On the one hand,
> a <- matrix (1:4, nrow=2)
> a <- data.frame (a)
> names (a) <- c("break","next")
> names (a)
[1] "break" "next"
On the other,
> a <- matrix (1:4, nrow=2)
> dimnames(a)
2003 Apr 04
3
creating function bodies using body()
I'm having trouble figuring out how to create a function using "body<-"
(). The help file for body() says that the argument should be a list of
R expressions. However if I try that I get an error:
> tmpfun <- function(a, b=2){}
> body(tmpfun) <- list(expression(z <- a + b),expression(z^2))
Error in as.function.default(c(formals(f), value), envir) :
2009 Apr 02
1
Updating a data frame
Folks,
Updating values in a table is simple in SAS or SQL, but I've wracked my
brain looking for an elegant solution in R to no avail thus far. Certainly
this is a common need that's been solved in dozens of different ways.
Given an initial dataframe nn and a smaller dataframe of updates uu, I'd
like to replace the values in
nn <- expand.grid('a'=1:4, 'b'=1:3)
2003 Sep 29
4
Data frame transpose
Hi All,
I want to ask if there is a transpose function for data frame like the
procedure of transpose in SAS? Because I want to partially transpose a
data frame which contains 5 columns (siteid, date, time, obs, mod), what
I want to do is to put time as the column variables along with siteid,
and date, and put obs and mod in the row names. specifically to
transpose a data frame:
siteid date
2005 Jul 12
4
Calculation of group summaries
I know R has a steep learning curve, but from where I stand the slope
looks like a sheer cliff. I'm pawing through the available docs and
have come across examples which come close to what I want but are
proving difficult for me to modify for my use.
Calculating simple group means is fairly straight forward:
data(PlantGrowth)
attach(PlantGrowth)
stack(mean(unstack(PlantGrowth)))
2005 Oct 07
2
Assign references
Folks,
I've run into trouble while writing functions that I hope will create
and modify a dataframe or two. To that end I've written a toy function
that simply sets a couple of variables (well, tries but fails).
Searching the archives, Thomas Lumley recently explained the <<-
operator, showing that it was necessary for x and y to exist prior to
the function call, but I haven't
2002 Aug 29
8
lme() with known level-one variances
Greetings,
I have a meta-analysis problem in which I have fixed effects
regression coefficients (and estimated standard errors) from identical
models fit to different data sets. I would like to use these results
to create pooled estimated regression coefficients and estimated
standard errors for these pooled coefficients. In particular, I would
like to estimate the model
\beta_{i} = \mu +
2003 Feb 11
3
Problems with Rcmd check on Win 2000 & rw1062
When I run Rcmd check on a package on my Windows 2000 machine, I get a
series of error messages like the following:
* checking generic/method consistency ...c:\DOCUME~1\R5018~1.WOO\LOCALS~1\Temp/R
utils138414013: cannot open c:DOCUME~1R5018~1.WOOLOCALS~1Temp/Rin138408157: no s
uch file
It looks as if a Windows style path to the temp directory is not being interpreted correctly, with backslashes
2001 May 30
2
environments
I would like to be able, inside a function, to create a new function, and
use it as part of a formula as an argument to, say, gnls or nlme. for
example:
MyTop <- function(data=dta) {
Cexp <- function(dose,A,B,m){...}
Model <- as.formula(paste("y","~ Cexp(",paste(formals(Cexp),collapse
=", "),")"))
MyCall <-
2009 Feb 10
7
ifelse()
I have a problem with ifelse(), I do not understand how it works.
> X<-c(2,2,1,1,0,0)
> str(X)
num [1:6] 2 2 1 1 0 0
> Y<-ifelse(X>0,1,0)
> Y
[1] 1 1 1 1 0 0
>
Can some one explain what is going on, I do not understand what ifelse is
doing in this case. Can someone explain the output Y.
Thanks
--
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2002 Feb 19
2
cdf of the standard normal distribution
Dear Experts,
I need to calculate the cdf of the standard normal distribution, i.e.
H(x) = 1/sqrt(2*pi) integral(exp(-z^2/2) dz), where z is b/w -infi to
infi.
I know there should be a way to do it in R, but did not know to do it.
I'd appreciate any help you could offer.
Charlie Liu
Graduate student intern at EPA/ECO
2002 Jan 23
4
driving R from Python (calldll?)
Sam Rushing's Python extension 'calldll' will supposedly give me access
to any DLL,
and presumably R.DLL in particular, from Python. I have no experience
manipulating DLLs as
yet. I am learning Python. I can't find any simple step-by-step
instructions on how
to get done what I want to do. Does anyone have experience with this?
Is there a
better way? Of course, one can use
2004 Jan 05
3
optim function : "BFGS" vs "L-BFGS-B"
Dear kind R-experts.
Does anybody have an experience to use optim function?
If yes, what is the main difference between two method "BFGS" vs
"L-BFGS-B"?
I used "BFGS" method and got what I wanted. But when I used "L-BFGS-B"
the error message said that "L-BFGS-B needs finite values of fn". So
that means
"BFGS" method can handle even if fn
2001 Jul 31
4
nlme: bug in getCovariateFormula (PR#1038)
I found that predict.gnls failed with a wierd error message about a
non-numeric argument to a binary vector in one of three nearly identical
uses.
Error in Inh/Ki : non-numeric argument to binary operator
(Inh and Ki are arguments to the function used in the formula for the
object whose predictions were requested).
It turns out that the problem is in getCovariateFormula().
The final line in
2004 May 19
2
POSIX to ts and back to POSIX
I am trying to use POSIX datetime objects rather than chron datetime
objects but am having difficulty with POSIX in a time series. My
question: Once a POSIXct vector is bound to a time series, is there a
function to convert back to POSIXct? The following code demonstrates
what I am trying to do.
> ts(as.POSIXct(strptime(tmp,"%m/%d/%Y %H:%M:%S")),freq=1440)
Time Series:
Start =
2011 Sep 16
3
Help writing basic loop
Hello,
I would like to write a loop to 1) run 100 linear regressions, and 2)
compile the slopes of all regression into one vector. Sample input data
are:
y1<-rnorm(100, mean=0.01, sd=0.001)
y2<-rnorm(100, mean=0.1, sd=0.01)
x<-(c(10,400))
#I have gotten this far with the loop
for (i in 1:100) {
#create the linear model for each data set
model1<-lm(c(y1[i],y2[i])~x)