

_O_p_t_i_o_n_s _S_e_t_t_i_n_g_s

     options(...)
     .Options

_A_r_g_u_m_e_n_t_s:

     ...: any options can be defined, using `name = value'.
          However, only the ones below are used in ``base
          R''.

          Further, `options('name') == options()['name']',
          see the example.

  prompt: a string, used for R's prompt; should usually end
          in a blank (`" "').

continue: a string setting the prompt used for lines which
          continue over one line.

   width: controls the number of characters on a line. You
          may want to change this if you resize the window
          that R is running in.

  digits: controls the number of digits to print when print-
          ing numeric values. It is a suggestion only.

  editor: sets the default text editor, e.g., for `edit'.

 browser: default HTML browser used by `help.start()'.

contrasts: the default contrasts used in model fitting such
          as `lm'.

expressions: sets a limit on the number of nested expres-
          sions that will be evaluated.   This is especially
          important on the Macintosh since stack overflow is
          likely if this is set too high.

na.action: the name of a function for treating missing
          values (`NA''s) for certain situations.

   pager: the (standalone) program used for displaying ASCII
          files on R's console.  Defaults to
          `$RHOME/bin/pager'.

papersize: the paper format used for graphics printing;
          currently read-only, set by environment variable
          R_PAPERSIZE, or in `config.site'.

printcmd: the command used for graphics printing; currently
          read-only, set by environment variable R_PRINTCMD,
          or in `config.site'.

show.signif.stars, show.coef.Pvalues: logical, affecting P
          value printing, see `print.coefmat'.

  ts.eps: the relative tolerance for certain time series
          (`ts') computations.

_D_e_s_c_r_i_p_t_i_o_n:

     `options' allows the user to set and examine a variety
     of global ``options'' which affect the way in which R
     computes and displays its results.

_D_e_t_a_i_l_s:

     Invoking `options()' with no arguments returns a list
     with the current values of the options.  `.Options' is
     another way to access this list ``read only''.

     Accessing current options, usually will work with
     `.Options$width' (e.g.), rather than `options("width")'
     which is a list of length one.

_V_a_l_u_e:

     A list (in any case) with the previous values of the
     options changed, or all options when no arguments were
     given.

_E_x_a_m_p_l_e_s:

     options() # printing all current options
     op <- options(); str(op) # nicer printing

     # .Options is the same:
     all(sapply(1:length(op), function(i) all(.Options[[i]] == op[[i]])))

     options('width')[[1]] == options()$width # the latter needs more memory
     options(digits=20)
     pi

     # set the editor, and save previous value
     old.o <- options(editor="nedit")
     old.o

     options(op)     # reset (all) initial options
     options('digits')

