Permit a mild protest on the word "appropriate" in this context. The
global assignment operator "<<-" provides, for my tastes, excessive
opportunities for problems. If I define "x" someplace else and then
call your function, it may change my "x" in ways that generate
considerable wailing and gnashing of teeth. Unless I assign the
function output to "x", then the action of your function will change my
"x" in ways I did not anticipate, possibly generating many problems for
me later -- with extreme difficulties in finding the source of the
problem. Moreover, if your library expects to later find in "x" what
your function stored there, there could be other problems, because I
might redefine "x" before you use it. The library might work fine when
you use it but not for someone else -- and tracing the problem can be
difficult.
I understand that "<<-" may allow your function f1 to call f2 and
have f2 change "x" in f1. However, if your f2 gets called some other
way or if the name of "x" is misspelled or changed in either f1 or f2,
we could be back to the situation I just described.
spencer graves
Brahm, David wrote:
> In a clean environment under R-2.1.0 on Linux:
>
>>x <- 1:5
>>x[3] <<- 9
>
> Error: Object "x" not found
>
> Isn't that odd? (Note x <<- 9 works just fine.)
>
> Why am I doing this? Because I'm stepping through code that
> normally lives inside a function, where "<<-" is appropriate.
>
> -- David Brahm ([EMAIL PROTECTED])
>
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--
Spencer Graves, PhD
Senior Development Engineer
PDF Solutions, Inc.
333 West San Carlos Street Suite 700
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