[R] What does the "<<-" operator mean?

Rolf Turner rolf.turner at xtra.co.nz
Thu Apr 21 23:39:03 CEST 2011

On 22/04/11 07:08, Cliff Clive wrote:
> I've been reading some code from an example in a blog post (
> http://www.maxdama.com/ here ) and I came across an operator that I hadn't
> seen before.  The author used a<<- operator to update a variable, like so:
> ecov_xy<<- ecov_xy+decay*(x[t]*y[t]-ecov_xy)
> At first I thought it was a mistake and tried replacing it with the usual<-
> assignment operator, but I didn't get the same results.  So what does the
> double arrow<<- operator do?

Install the "fortunes" (if you haven't already) and see:



             Rolf Turner

More information about the R-help mailing list