

   FFiinndd AAllll NNaammeess iinn aann EExxpprreessssiioonn

        all.names(expr, functions = T,
                max.names = 200, unique = F)
        all.vars(expr, functions = F,
                max.names = 200, unique = T)

   AArrgguummeennttss::

       expr: an expression or call from which the names are to
             be extracted.

   functions: a logical value indicating whether function names
             should be included in the result.

   max.names: the maximum number of names to be returned.

     unique: a logical value which indicates whether duplicate
             names should be removed from the value.

   VVaalluuee::

        These functions return a character vector containing
        all the names which occur in an expression or call.
        These functions differ only in the default values for
        their arguments.

   EExxaammpplleess::

        all.names(expression(sin(x+y)))
        all.vars(expression(sin(x+y)))

