R help - Oct 2012 - Basic question about: <<- and method start with dot.

Dear list,

When I read some source code, I find lot of place used  symbol <<- , e.g.

lastTime <<- newTime;

What is the meaning here?

Also, I find some method with the name start with dot, e.g.

.RowStandardizeCentered = function(x) {
	div = sqrt( rowSums(x^2) );
	div[ div == 0 ] = 1;
	return( x/div );
}

What is the special meaning for the method name start with a dot?

Thank you very much in advance.

On 02/10/12 17:00, Fabrice Tourre wrote:
> Dear list,
>
> When I read some source code, I find lot of place used  symbol <<- ,
e.g.
>
> lastTime <<- newTime;
>
> What is the meaning here?
?"<<-"

See also:

     require("fortunes")
     fortune("<<-")
>
> Also, I find some method with the name start with dot, e.g.
>
> .RowStandardizeCentered = function(x) {
> 	div = sqrt( rowSums(x^2) );
> 	div[ div == 0 ] = 1;
> 	return( x/div );
> }
>
> What is the special meaning for the method name start with a dot?
?ls
Note the argument "all.names".

     cheers,

         Rolf Turner

On Oct 2, 2012, at 06:00 , Fabrice Tourre wrote:
> Dear list,
> 
> When I read some source code, I find lot of place used  symbol <<- ,
e.g.
> 
> lastTime <<- newTime;
> 
> What is the meaning here?
Did you check help("<<-") ? The explanation there seems at least
as clear as anything I could cook up in a quick mail...
> 
> Also, I find some method with the name start with dot, e.g.
> 
> .RowStandardizeCentered = function(x) {
> 	div = sqrt( rowSums(x^2) );
> 	div[ div == 0 ] = 1;
> 	return( x/div );
> }
> 
> What is the special meaning for the method name start with a dot?
It means nothing in particular, except that such objects don't show up in
ls() by default. The _intention_ is usually that the function is only to be used
internally and not for end-user use.


-- 
Peter Dalgaard, Professor,
Center for Statistics, Copenhagen Business School
Solbjerg Plads 3, 2000 Frederiksberg, Denmark
Phone: (+45)38153501
Email: pd.mes at cbs.dk  Priv: PDalgd at gmail.com