search for: unevaluated

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...

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 matrice...

...ate 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 to be a character string, with just ONE element. I tried: toString(substitute(apply(exp.des[1:10,], 1, one.row, parms=parameters))) but it modifies the expression (e.g. removing parenthesis), which I do not want. Any idea on how to c...

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") newexp=newexp+eval(exp0,ls)/factorial(i)...

-------- 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...

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 alternati...

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>> @

...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 working quite well but I would appreciate advice on programming the most elegant solution to passing unevaluated arguments. Here's the situation. xYplot needs to fiddle with arguments formula and data (which I default to sys.frame(sys.parent()) which I believe will pass through to xyplot OK). There are several arguments passed through to xyplot which were the "..." arguments to xYplot. I wan...

...cl 0x39174b0 prev 0x3917130 <col:25, col:32> struct Inner | | |-CXXMethodDecl 0x3917540 <col:43, col:51> f 'int (void)' | | | `-CompoundStmt 0x390f680 <col:50, col:51> | | |-CXXConstructorDecl 0x3917610 <col:32> Inner 'void (void)' inline noexcept-unevaluated 0x3917610 | | | `-CompoundStmt 0x3918370 <col:32> | | |-CXXConstructorDecl 0x3917770 <col:32> Inner 'void (const struct Outer<float>::Inner<int *> &)' inline noexcept-unevaluated 0x3917770 | | | `-ParmVarDecl 0x39178b0 <col:32> 'const struct...

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() function such that I can call: expr0 <- foo({ x <- 1 }) expr1 &l...

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 say), which would be expression(x * x + 3) in this case...

?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"

...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 return an evaluated result but doesn't? > R.version.string # Vista [1] "R version 2.6.0 alpha (2007-09-06 r42791)"

Hi, A question (& possible suggestion) about function calls. Is there an R idiom to eliminate the redundancy in the following common situation? foo <- function(x, control=ComplicatedDefault) { etc. } plotfoo <- function(x, foocontrol=ComplicatedDefault, ...) { y <- foo(x, control=foocontrol) lines(x,y,...) } The idea is that there are MANY

...ly(...)) C code, > when S3 dispatch of primitive functions should happen. The bug is in do_is, which uses CHAR(PRINTNAME(CAR(call))), and when called from lapply that gives "FUN" not "is.numeric". The root cause is the following comment FUN = CADR(args); /* must be unevaluated for use in e.g. bquote */ and hence that the function in the *call* passed to do_is can be unevaluated. > Here's an R scriptlet exposing a 2nd example > > ### lapply(list, FUN) > ### ------------------ seems to sometimes fail for > ### .Primitive S3-generic functions > >...

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...