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: / lib / ruby / gems / 3.0.0 / gems / rexml-3.2.5 / doc / rexml / tasks / rdoc /
Filename : node.rdoc
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== Module Node

:include: ../tocs/node_toc.rdoc

=== Siblings

==== Task: Find Previous Sibling

Use method
{Node.previous_sibling_node}[../../../../REXML/Node.html#method-i-previous_sibling]
to retrieve the previous sibling:

  d = REXML::Document.new('<root><a/><b/><c/></root>')
  b = d.root[1]           # => <b/>
  b.previous_sibling_node # => <a/>

==== Task: Find Next Sibling

Use method
{Node.next_sibling_node}[../../../../REXML/Node.html#method-i-next_sibling]
to retrieve the next sibling:

  d = REXML::Document.new('<root><a/><b/><c/></root>')
  b = d.root[1]       # => <b/>
  b.next_sibling_node # => <c/>

=== Position

==== Task: Find Own Index Among Siblings

Use method
{Node.index_in_parent}[../../../../REXML/Node.html#method-i-index_in_parent]
to retrieve the 1-based index of this node among its siblings:

  d = REXML::Document.new('<root><a/><b/><c/></root>')
  b = d.root[1]     # => <b/>
  b.index_in_parent # => 2

=== Recursive Traversal

==== Task: Traverse Each Recursively

Use method
{Node.each_recursive}[../../../../REXML/Node.html#method-i-each_recursive]
to traverse a tree of nodes recursively:

  xml_string = '<root><a><b><c></c></b><b><c></c></b></a></root>'
  d = REXML::Document.new(xml_string)
  d.root.each_recursive {|node| p node }

Output:

  <a> ... </>
  <b> ... </>
  <c/>
  <b> ... </>
  <c/>

=== Recursive Search

==== Task: Traverse Each Recursively

Use method
{Node.find_first_recursive}[../../../../REXML/Node.html#method-i-find_first_recursive]
to search a tree of nodes recursively:

  xml_string = '<root><a><b><c></c></b><b><c></c></b></a></root>'
  d = REXML::Document.new(xml_string)
  d.root.find_first_recursive {|node| node.name == 'c' } # => <c/>

=== Representation

==== Task: Represent a String

Use method {Node.to_s}[../../../../REXML/Node.html#method-i-to_s]
to represent the node as a string:

  xml_string = '<root><a><b><c></c></b><b><c></c></b></a></root>'
  d = REXML::Document.new(xml_string)
  d.root.to_s # => "<root><a><b><c/></b><b><c/></b></a></root>"

=== Parent?

==== Task: Determine Whether the Node is a Parent

Use method {Node.parent?}[../../../../REXML/Node.html#method-i-parent-3F]
to determine whether the node is a parent;
class Text derives from Node:

  d = REXML::Document.new('<root><a/>text<b/>more<c/></root>')
  t = d.root[1] # => "text"
  t.parent?     # => false

Class Parent also derives from Node, but overrides this method:

  p = REXML::Parent.new
  p.parent? # => true