Mu22v3MAPCOUNTS          package:Mu22v3.db          R 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 _M_u_2_2_v_3._d_b

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

     Mu22v3MAPCOUNTS provides the "map count" (i.e. the count of mapped
     keys) for each map in package Mu22v3.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:

       Mu22v3MAPCOUNTS
       mapnames <- names(Mu22v3MAPCOUNTS)
       Mu22v3MAPCOUNTS[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 Mu22v3.db
       checkMAPCOUNTS("Mu22v3.db")

