Module Node¶ ↑

Tasks on this page:

• Siblings

  • Task: Find Previous Sibling

  • Task: Find Next Sibling

• Position

  • Task: Find Own Index Among Siblings

• Recursive Traversal

  • Task: Traverse Each Recursively

• Recursive Search

  • Task: Traverse Each Recursively

• Representation

  • Task: Represent a String

• Parent?

  • Task: Determine Whether the Node is a Parent

Siblings¶ ↑

Task: Find Previous Sibling¶ ↑

Use method Node.previous_sibling_node 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 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 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 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 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 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? 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