mgu74cMAPCOUNTS          package:mgu74c.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_g_u_7_4_c._d_b

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

     mgu74cMAPCOUNTS provides the "map count" (i.e. the count of mapped
     keys) for each map in package mgu74c.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:

       mgu74cMAPCOUNTS
       mapnames <- names(mgu74cMAPCOUNTS)
       mgu74cMAPCOUNTS[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 mgu74c.db
       checkMAPCOUNTS("mgu74c.db")

