_S_e_l_e_c_t _O_n_e _o_f _a _L_i_s_t _o_f _A_l_t_e_r_n_a_t_i_v_e_s
	
	     switch(EXPR, ...)
	
	_A_r_g_u_m_e_n_t_s:
	
	        EXPR : an expression that evaluates to a number or a
	               character string
	
	         ... : the list of alternatives, given explicitly
	
	_D_e_s_c_r_i_p_t_i_o_n:
	
	     switch evaluates EXPR if the value is an integer
	     between 1 and nargs()-1 then the corresponding element
	     of ... is evaluated and the result returned.  If EXPR
	     returns a character string then that string is used to
	     match the names of the elements in .... If there is an
	     exact match then that element is evaluated and the
	     result returned.
	
	_E_x_a_m_p_l_e_s:
	
	     centre <- function(x, type) {
	     switch(type,
	             mean=mean(x),
	             median=median(x),
	          trimmed=mean(x, trim=.1))
	     }
	     x <- rcauchy(10)
	     centre(x, "mean")
	     centre(x, "median")
	     centre(x, "trimmed")