[R] What is the . in formula ~. syntax?

[Michael Weylandt]

On Nov 23, 2012, at 4:26 AM, Brian Feeny <bfeeny at mac.com> wrote:

> I know if I have a dataframe with columns y, x1, x2 and I wish to have y as my y value and x1 and x2 as x values I can do:
> y ~ x1 + x2
> 
> or 
> 
> y ~.
> 
> but can someone explain what . actually is or what its transposed into?

Everything not already stated. 

rmw

> 
> I searched for this with no success, reading the "formula" manual pages.
> 
> Brian
> 
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