title: How can I see all argument options in R?
body: <p>This seems like a stupid question, but I have not been able to find the answer by googling.</p>
  
  <p>R Documentation often does not outline all possible values for particular arguments. Is there a command to print that information? </p>
  
  <p>For example, I would like to draw some maps using the function <code>map()</code> in the <code>maps</code> package. The R Documentation states for the region argument:</p>
  
  <blockquote>
    <p>regions: character vector that names the polygons to draw. Each
    database is composed of a collection of polygons, and each polygon has
    a unique name. When a region is composed of more than one polygon, the
    individual polygons have the name of the region, followed by a colon
    and a qualifier, as in michigan:north and michigan:south. Each element
    of regions is matched against the polygon names in the database and,
    according to exact, a subset is selected for drawing. The default
    selects all polygons in the database.</p>
  </blockquote>
  
  <p>Is it possible to get a list of the region names?</p>