ISFIELD  ISFIELD Test for Existence of a Structure Field


Usage
 
 Given a structure array, tests to see if that structure
 array contains a field with the given name.  The syntax
 for its use is
 
   y = isfield(x,field)
 
 and returns a logical 1 if x has a field with the 
 name field and a logical 0 if not.  It also returns
 a logical 0 if the argument x is not a structure array.
 