[R] Is = now the same as <- in assigning values

Peter Dalgaard P.Dalgaard at biostat.ku.dk
Thu Dec 18 16:26:23 CET 2008


Kenn Konstabel wrote:

> This is legal but doesn't do what you probably expect -- although
> documentation for `<-` says the value (returned by <-) is 'value' i.e.
> whatever is on the right side ...
> 
>> x<-NULL  # just to make sure it's not yet 42
>> foo <- function(a) a
>> foo({x = 42})   # no result

Wrong...

> bar <- foo({x = 42})
> bar
[1] 42


What you're seeing is effectively

> foo(invisible(42))

i.e. the result is there, just not printing.



-- 
   O__  ---- Peter Dalgaard             Øster Farimagsgade 5, Entr.B
  c/ /'_ --- Dept. of Biostatistics     PO Box 2099, 1014 Cph. K
 (*) \(*) -- University of Copenhagen   Denmark      Ph:  (+45) 35327918
~~~~~~~~~~ - (p.dalgaard at biostat.ku.dk)              FAX: (+45) 35327907



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