On 02-Feb-2015 11:58:10 Rolf Turner wrote: > > On 02/02/15 14:26, Steve Taylor wrote: > >> All the more reason to use = instead of <- > > Couldn't agree less, Steve. The "<-" should be used for assignment. The > "=" sign should be reserved for handling function arguments in the > "name=value" form. Doing anything else invites confusion and > occasionally chaos. > > Lots of examples have been given in the past involving syntax of the > form foo(x = y) and foo(x <- y). > > cheers, > Rolf > -- > Rolf Turner
As well as agreering with Rolf, it should also be said that Steve's advice "All the more reason to use = instead of <-" is not applicable in this context, which was: which( frame$var>4 ) # no problem which( frame$var<-4 ) # huge problem: frame$var is destroyed There is no place for an "=" here! What does not seems to have been mentioned so far is that this kind of thing can be safely wrapped in parentheses: which( frame$var>4 ) # no problem oper which( frame$var<(-4) ) # [again no problem] Personally, I'm prone to using parentheses if I have any feeling that a "gotcha" may be lurking -- not only in the distinction between "var<-4" and "var< -4", but also to be confident that, for instance, my intentions are not being over-ridden by operator precedence rules. Some people object to code "clutter" from parentheses that could be more simply replaced (e.g. "var< -4" instead of "var<(-4)"), but parentheses ensure that it's right and also make it clear when one reads it. Best wishes to all, Ted. ------------------------------------------------- E-Mail: (Ted Harding) <ted.hard...@wlandres.net> Date: 02-Feb-2015 Time: 12:43:51 This message was sent by XFMail ______________________________________________ R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
