programming questions
yikes. this is all my fault. it was the first thing that I ever defined when I started using R. is.defined <- function(name) exists(as.character(substitute(name))) I presume there is something much better... /iaw
On Wed, Nov 3, 2010 at 2:12 PM, Erik Iverson <eriki at ccbr.umn.edu> wrote:
ivo welch wrote:
quick programming questions. ?I want to "turn on" more errors. ?there are two traps I occasionally fall into. * I wonder why R thinks that a variable is always defined in a data frame. ? ? > is.defined(d) ? ? [1] FALSE ? ? > d= data.frame( x=1:5, y=1:5 ) ? ? > is.defined(d$z) ? ? [1] TRUE ? ? > is.defined(nonexisting$garbage) ? ? [1] TRUE
Which package/version of R is the 'is.defined' function in? I don't seem to have it here on 2.11.1, which I know is not the latest version of R. What does 'defined' mean?
this is a bit unfortunate for me, because subsequent errors become less clear. ? right now, I need to do '(is.defined(d) and !is.null(d$z))' to check that my function inputs are valid. ?It would be nicer if one could just write "if (is.defined(d$z)".
"z" %in% names(d) ?
* is there a way to turn off automatic recycling? ?I would rather get an error than unexpected recycling. ?I can force recycling with rep() when I need to. regards, /iaw ---- Ivo Welch (ivo.welch at brown.edu, ivo.welch at gmail.com)
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