>>>>> "Petr" == Petr Pikal <[EMAIL PROTECTED]> >>>>> on Mon, 07 Jun 2004 13:12:07 +0200 writes:
Petr> Hi On 7 Jun 2004 at 12:57, zze-PELAY Nicolas Petr> FTRD/DMR/BE wrote: >> Hello, >> >> I'd like to know if I can modify a constant value with a >> function. >> >> Example : >> >> a=4 >> >> f1<-function() {a=3} Petr> Simply use <<- in the function. yes. Petr> But I am not sure if this is recommendable way of Petr> items manipulating in R. Thank you, Petr. Indeed, I am even sure that it *is* not recommended: Very much recommended is to write a function such that 1) it only uses its arguments (and no global variables) as input 2) provides all its results as return() value, often a list(). There are exceptions to these rules, e.g. for plot() functions, "2)" will often not be true [and for print.*() methods, the unwritten R standard asks for print.*(x, ....) to return(invisible(x))] "1)" {and sometimes 2) as well} will be violated for UI (not only GUI) functions. When working very large objects, it can make sense to violate both "1)" and "2)".. -- but that's really for more advanced programming. Martin Maechler ______________________________________________ [EMAIL PROTECTED] mailing list https://www.stat.math.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html