[R] assignment function

[Peter Dalgaard BSA]

Christian Hoffmann <christian.hoffmann at wsl.ch> writes:

> Hi,
> 
> I am trying to create the assignment function:
> "substring<-" <- function(text, first, last=100000, sub) {
....
> Checking
> > x <- 'this string'
> > substring(x, 3, 4) <- 'IS'
> 
> will not result in
> > x [1] "thIS string"
> 
> but will cry
> Error in substr<-(*tmp*, 3, 4, value = "IS") : 
> 	unused argument(s) (value ...)
> 
> A cat(is.character(first),"\n") after the first line will not even be
> executed.

For reasons that I have forgotten, the value of an assignment function
is always passed using an argument called "value", so try changing
"sub" to "value".

(I haven't *completely* forgotten the reason. It is something with
assignment functions like "[<-.data.frame" taking a variable number of
arguments.)

-- 
   O__  ---- Peter Dalgaard             Blegdamsvej 3  
  c/ /'_ --- Dept. of Biostatistics     2200 Cph. N   
 (*) \(*) -- University of Copenhagen   Denmark      Ph: (+45) 35327918
~~~~~~~~~~ - (p.dalgaard at biostat.ku.dk)             FAX: (+45) 35327907
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