[R] alist()

[gah5 at comcast.net]

Peter Dalgaard <p.dalgaard at biostat.ku.dk> wrote:
(regarding adding NULL elements to a list)

> > x["two"] <- list(NULL)

This seems to work. 

In the actual case, it is assigning from a variable that may 
or may not be null, 
for example:

two<-NULL
x["two"]<-list(two)

It seems to work, and not do what it looks like, add a list of
length one.   I suppose I should realize by now that scalars
are just like lists of length one, but this still wasn't obvious.

thanks,

-- glen