dumpObjects             package:filehash             R Documentation

_D_u_m_p _o_b_j_e_c_t_s _o_f _d_a_t_a_b_a_s_e

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

     Dump R objects to a filehash database

_U_s_a_g_e:

     dumpObjects(..., list = character(0), dbName, type = NULL, envir = parent.frame())
     dumpImage(dbName = "Rworkspace", type = NULL)
     dumpDF(data, dbName = NULL, type = NULL)
     dumpList(data, dbName = NULL, type = NULL)

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

     ...: R objects to dump

    list: character vector of names of objects to dump

  dbName: character, name of database to which objects should be dumped

    type: type of database to create

   envir: environment from which to obtain objects

    data: a data frame or a list

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

     Objects dumped to a database can later be loaded via 'dbLoad' or
     can be accessed with 'dbFetch', 'dbList', etc. Alternatively, the
     'with' method can be used to evaluate code in the context of a
     database.  If a database with name 'dbName' already exists,
     objects will be inserted into the existing database (and values
     for already-existing keys will be overwritten).

     'dumpDF' is different in that each variable in the data frame is
     stored as a separate object in the database.  So each variable can
     be read from the database separately rather than having to load
     the entire data frame into memory.  'dumpList' works in a simlar
     way.

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

     An object of class '"filehash"' is returned and a database is
     created.

_A_u_t_h_o_r(_s):

     Roger D. Peng

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

     data <- data.frame(y = rnorm(100), x = rnorm(100), z = rnorm(100))
     db <- dumpDF(data, dbName = "dataframe.dump")
     fit <- with(db, lm(y ~ x + z))
     summary(fit)

     db <- dumpList(list(a = 1, b = 2, c = 3), "list.dump")
     db$a

