= or <-

Thanks Erik and Gabor for this precision,

I guess that my misunderstanding of these concepts came from some bad 
habits I took during my self-learning experience of R (especially, 
copy/paste of old codes where <- was used for function arguments and did 
not produce error messages).

Sebastien

Erik Iverson a ?crit :

S?bastien wrote:

Dear R-users,

I have written a short VB application to clean and format my R code. 
Everything works fine except one small issue that I did not expected; 
it is related the automatic replacement of assignment signs from "=" 
to "<-". Most functions or arguments seem to accept either = or <-, 
but some don't (e.g.  ls(all=TRUE)). The result is that my supposedly 
clean codes do not run anymore :-(
Is there a way to know the list of arguments/functions that do not 
accept "<-" signs ?

You are surely mixing two concepts here.

When you are doing an assignment of a value to a variable, you may use 
either <- or =.  Example

a <- 2
a = 2

both bind the value of 2 to the symbol "a".

When you call a function, for example ls, you can specify the argument 
names, such as ls(all = TRUE).

If you attempted ls(all <- TRUE), the value of TRUE will be assigned 
to the symbol 'all', and then ls will be evaluated with its first 
argument "names" as TRUE, which produces your error.  You almost 
certainly want ls(all = TRUE).  After the error, try typing 'all' at 
the R prompt.  The 'all' function definition has now been overwritten 
and is simply TRUE, which you probably do not want either.

So, there really is no concept of whether or not a function "accepts 
<- signs".  You want to use = in your function calls, since the '<-' 
method is actually assigning values.

Hope that helps,
Erik

Thanks in advance.

Sebastien