Roberts2005AnnotationMAPCOUNTSpackage:Roberts2005Annotation.dbR Documentation

_N_u_m_b_e_r _o_f _m_a_p_p_e_d _k_e_y_s _f_o_r _t_h_e _m_a_p_s _i_n _p_a_c_k_a_g_e _R_o_b_e_r_t_s_2_0_0_5_A_n_n_o_t_a_t_i_o_n._d_b

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

     Roberts2005AnnotationMAPCOUNTS provides the "map count" (i.e. the
     count of mapped keys) for each map in package
     Roberts2005Annotation.db.

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

     This "map count" information is precalculated and stored in the
     package annotation DB. This allows some quality control and is
     used by the 'checkMAPCOUNTS' function defined in AnnotationDbi to
     compare and validate different methods (like 'count.mappedkeys(x)'
     or 'sum(!is.na(as.list(x)))') for getting the "map count" of a
     given map.

_S_e_e _A_l_s_o:

     'mappedkeys', 'count.mappedkeys', 'checkMAPCOUNTS'

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

       Roberts2005AnnotationMAPCOUNTS
       mapnames <- names(Roberts2005AnnotationMAPCOUNTS)
       Roberts2005AnnotationMAPCOUNTS[mapnames[1]]
       x <- get(mapnames[1])
       sum(!is.na(as.list(x)))
       count.mappedkeys(x)   # much faster!

       ## Check the "map count" of all the maps in package Roberts2005Annotation.db
       checkMAPCOUNTS("Roberts2005Annotation.db")

