xmlFlatListTree             package:XML             R Documentation

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_i_n_f_o_r_m_a_t_i_o_n _a_b_o_u_t _p_a_r_e_n_t_s _a_n_d _c_h_i_l_d_r_e_n

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

     These (and related internal) functions allow us to represent trees
     as a simple, non-hierarchical collection of nodes along with
     corresponding tables that identify the parent and child
     relationships. This is different from representing a tree as a
     list of lists of lists ...  in which each node has a list of its
     own children. In a functional language like R, it is not possible
     then for the children to be able to identify their parents.

     We use an environment to represent these flat trees.  Since these
     are mutable without requiring the change to be reassigned, we can
     modify a part of the tree locally without having to reassign the
     top-level object.

     We can use either a list (with names) to store the nodes or a hash
     table/associative array that uses names. There is a non-trivial
     performance difference.

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

     xmlHashTree(nodes = list(), parents = character(), children = list(), 
                  env = new.env(TRUE))
     xmlFlatListTree(nodes = list(), parents = character(), children = list(), env = new.env(), n = 200)

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

   nodes: a collection of existing nodes that are to be added to the
          tree. These are used to initialize the tree. If this is
          specified, you must also specify 'children' and 'parents'. 

 parents: the parent relationships for the nodes given by 'nodes'.

children: the children relationships for the nodes given by 'nodes'.

     env: an environment in which the information for the tree  will be
          stored. This is essentially the tree object as it allows us
          to modify parts of the tree without having to reassign the
          top-level object.    Unlike most R data types, environments
          are mutable. 

       n: for 'xmlFlatListTree', this is used as the default size to
          allocate for the list containing the nodes

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

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

     An object of class XMLFlatTree which is specialized to
     'XMLFlatListTree' by the 'xmlFlatListTree' function and
     'XMLHashTree' by the 'xmlHasTree' function. Both are simply the
     environment.

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

     Duncan Temple Lang

_R_e_f_e_r_e_n_c_e_s:

     <URL: http://www.w3.org/XML>

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

     'xmlTreeParse' 'xmlTree' 'xmlOutputBuffer' 'xmlOutputDOM'

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

