search for: unevaluable

Hi, I'm trying to get ...as a list of unevaluated arguments, ie. substitute(list(...)) gives me an unevaluated list of the arguments, but I want a list of the unevaluated arguments. My attempts so far: (function(...) substitute(...))(a=1, b=a) # Only returns first (function(...) substitute(list(...)))(a=1, b=a) # Unevaluated list, not list of unevaluated (function(...)

Hi, How to turn a character string into an unevaluated R object? I want to load some files in a directory into data matrix R objects. I could do this with read.table and assign (see below). Then, I want to turn the character string representing a file name (the evaluated expression of i) into an unevaluated R object. Basically, I want to create matrices whose names are the same as the related file

Hi R-users, I would like to create an expression without evaluating it. Then paste that expression to an object. Example: Result <- paste('Result', 1, sep="") paste(Result, substitute(apply(exp.des[1:10,], 1, one.row, parms=parameters)), sep="<-") However this pastes EACH element of the unevaluated expression. Instead I just would like the expression

Hello, x<- "something(a+b) + c" is there any function F such that F(x) gives me the unevaluated value of x, i.e. something(a+b)+c I would appreciate any help on this thanks --------------------------------- [[alternative HTML version deleted]]

HI, As I'm trying to compute Taylor series, I'm having problems in adding and multiplying unevaluated expressions. I searched for a solution but found none. my Taylor function works fine for evaluating functions as you can see here: rTaylorVal=function(exp,x0,dx,n) { ls=list(x=x0) newexp=eval(exp,ls) exp0=exp for (i in 1:n){ exp0=D(exp0,"x")

-------- Original-Nachricht -------- Betreff: Re: [R] Adding and Multiplying two Unevaluated Expressions Datum: Tue, 01 Dec 2009 23:49:39 +0100 Von: Benjamin M?ller <ben_mueller.bm at web.de> An: Rolf Turner <r.turner at auckland.ac.nz> Referenzen: <20091201144125.316310 at gmx.net> <8E40E49F-E8FC-4FBD-8CC5-93789FFB0E53 at auckland.ac.nz> This works fine for your

Folks: Herein is a suggestion for a little R convenience function mainly to obtain unevaluated ... function arguments. It arose from a query on R-help on how to get these arguments. The standard (I think) idiom to do this is via match.call(expand.dots=FALSE)$... However, Bill Dunlap pointed out that this repeats the argument matching of the function call and suggested a couple of alternatives

Hi, Consider the following (much simplified) Sweave example: -------------- First, we set the value of $x$: <<chunk1,eval=FALSE>>= x <- 1 @ Then we set the value of $y$: <<chunk2,eval=FALSE>>= y <- 2 @ Thus, the overall algorithm has this structure: <<combined,eval=FALSE>>= <<chunk1>> <<chunk2>> @

Thanks to Deepayan Sarkar (lattice) and Paul Murrell (grid) I have nearly finished porting the Hmisc library's xYplot function to R. xYplot extends xyplot to allow for error bars, bands, and a few other features. In S-Plus I extended the Trellis function xyplot mainly by writing panel.xYplot. In R, xyplot contains a lot of code, so I implemented xYplot by calling xyplot from it. Things are

I was looking at the ClassTemplatePartialSpecializationDecl::getInstantiatedFromMember documentation, in the included example it says: "(..) the instantiation of Outer<float>::Inner<int*> will end up instantiating the partial specialization Outer<float>::Inner<U*> (...)". To understand the concept better, I dumped the AST for the following code:

Given the extremely simple package at https://github.com/jimhester/testUnload, which includes only one S3 method 'print.object' the following code produces a lazy load error from a new R session (R-devel r69801) install.packages("testUnload", repos = NULL) library("testUnload") unloadNamespace("testUnload") install.packages("testUnload", repos =

Hi, I'm trying to use R to get eigenvalues and eigenvectors of a matrix whose elements are of the form (2 * lambda), -(lambda + mu), etc. I'd like R to treat this matrix as a numeric matrix without treating lambda and mu as variable names but rather as some sort of atomic quantities (and hence give eigenvectors in terms of mu and/or lambda). MatLab and Mathematica both do this,

Hi there, Suppose the cmd is "a<-3", I can parse the cmd sexp with R_ParseVector and eval it. My question is - is it possible to parse a cmd like "a <- ?", afterwards evaluation will give corresponding result depend on different argument? In other words, '?' is just a placeholder. Thanks. Xin [[alternative HTML version deleted]]

This may have been asked before, but is there an elegant way to check whether an variable/argument passed to a function is a "parse tree" for an (unevaluated) expression or not, *without* evaluating it if not? Currently, I do various rather ad hoc eval()+substitute() tricks for this that most likely only work under certain circumstances. Ideally, I'm looking for a isParseTree()

Hi, I am looking for a way to find out the last expression that was entered by the user, similar to ".Last.value", but for the unevaluated expression instead of the evaluated one. Example: > x <- 4 > x*x + 3 [1] 19 > .Last.value # that's the evaluated last expression [1] 19 # but I am looking for the unevaluated expression (".Last.expression", so to

?bquote says it returns an expression but, in fact, it typically (though not always) returns a call object: > class(bquote(a+b)) [1] "call" > class(bquote(1)) [1] "numeric"

The last two lines of example(delayedAssign) give this: > e <- (function(x, y = 1, z) environment())(1+2, "y", {cat(" HO! "); pi+2}) > (le <- as.list(e)) # evaluates the promises $x <promise: 0x032b31f8> $y <promise: 0x032b3230> $z <promise: 0x032b3268> which contrary to the comment appears unevaluated. Is the comment wrong or is it supposed to

...o "..." in that it has such restricted use. I do recognize that since the user can inspect (and construct?) code, an expression for the empty value would be accessible as formals(plotfoo)$foocontrol or as substitute(foocontrol) evaluated within plotfoo(x). But this expression could be unevaluable, just as formals(plotfoo)$x is unevaluable. (Of course these two unevaluable expressions should be different, so that the user of formals() can see that x is a required argument and foocontrol isn't.) An alternative is to make this expression evaluable. Suppose we say that it evaluates to a...

On Wed, 30 Jul 2008, Martin Maechler wrote: >>>>>> "RobMcG" == McGehee, Robert <Robert.McGehee at geodecapital.com> >>>>>> on Tue, 29 Jul 2008 15:40:37 -0400 writes: > > RobMcG> FYI, > RobMcG> I've tried posting the below message twice to the bug tracking system, > > [....... r-bugs problems discussed in a

Hi R Graphics Gurus I am unable to figure out this issues with unevaluated expressions. I'm trying to create a graphic where I calculate the residual from a regression and want to mark each residual with its observation number. So something like plot(0,0, type = "n", xlim = c(0,10)) for(i in 1:10){ text(i, 0, substitute(paste(epsilon[i]))) } except that i end up pasting