Class: REXML::Elements

Class REXML::Elements |
In: | rexml/element.rb
Parent: | Object

A class which provides filtering of children for Elements, and XPath search support. You are expected to only encounter this class as the `element.elements` object. Therefore, you are not expected to instantiate this yourself.

Methods

[] []= add delete delete_all each empty? index new size to_a

Included modules

Enumerable

Public Class methods

new(parent)

Constructor

parent: | the parent Element

Public Instance methods

[]( index, name=nil)

Fetches a child element. Filters only Element children, regardless of the XPath match.

index: | the search parameter. This is either an Integer, which will be used to find the index'th child Element, or an XPath, which will be used to search for the Element. Because of the nature of XPath searches, any element in the connected XML document can be fetched through any other element. The Integer index is 1-based, not 0-based. This means that the first child element is at index 1, not 0, and the +n+th element is at index `n`, not `n-1`. This is because XPath indexes element children starting from 1, not 0, and the indexes should be the same.
name: | optional, and only used in the first argument is an Integer. In that case, the index'th child Element that has the supplied name will be returned. Note again that the indexes start at 1.
Returns: | the first matching Element, or nil if no child matched

     doc = Document.new '<a><b/><c id="1"/><c id="2"/><d/></a>'
     doc.root.elements[1]       #-> <b/>
     doc.root.elements['c']     #-> <c id="1"/>
     doc.root.elements[2,'c']   #-> <c id="2"/>

[]=( index, element )

Sets an element, replacing any previous matching element. If no existing element is found ,the element is added.

index: | Used to find a matching element to replace. See []().
element: | The element to replace the existing element with the previous element
Returns: | nil if no previous element was found.

     doc = Document.new '<a/>'
     doc.root.elements[10] = Element.new('b')    #-> <a><b/></a>
     doc.root.elements[1]                        #-> <b/>
     doc.root.elements[1] = Element.new('c')     #-> <a><c/></a>
     doc.root.elements['c'] = Element.new('d')   #-> <a><d/></a>

empty?()

Returns `true` if there are no `Element` children, `false` otherwise

index(element)

Returns the index of the supplied child (starting at 1), or -1 if the element is not a child

element: | an `Element` child

delete(element)

Deletes a child Element

element: | Either an Element, which is removed directly; an xpath, where the first matching child is removed; or an Integer, where the n'th Element is removed.
Returns: | the removed child

     doc = Document.new '<a><b/><c/><c id="1"/></a>'
     b = doc.root.elements[1]
     doc.root.elements.delete b           #-> <a><c/><c id="1"/></a>
     doc.elements.delete("a/c[@id='1']")  #-> <a><c/></a>
     doc.root.elements.delete 1           #-> <a/>

delete_all( xpath )

Removes multiple elements. Filters for Element children, regardless of XPath matching.

xpath: | all elements matching this String path are removed.
Returns: | an Array of Elements that have been removed

     doc = Document.new '<a><c/><c/><c/><c/></a>'
     deleted = doc.elements.delete_all 'a/c' #-> [<c/>, <c/>, <c/>, <c/>]

add(element=nil)

Adds an element

element: | if supplied, is either an Element, String, or Source (see Element.initialize). If not supplied or nil, a new, default Element will be constructed
Returns: | the added Element

     a = Element.new 'a'
     a.elements.add Element.new 'b'  #-> <a><b/></a>
     a.elements.add 'c'              #-> <a><b/><c/></a>

each( xpath=nil, &block) {|e if e.kind_of? Element }| ...}

Iterates through all of the child Elements, optionally filtering them by a given XPath

xpath: | optional. If supplied, this is a String XPath, and is used to filter the children, so that only matching children are yielded. Note that XPaths are automatically filtered for Elements, so that non-Element children will not be yielded

     doc = Document.new '<a><b/><c/><d/>sean<b/><c/><d/></a>'
     doc.root.each {|e|p e}       #-> Yields b, c, d, b, c, d elements
     doc.root.each('b') {|e|p e}  #-> Yields b, b elements
     doc.root.each('child::node()')  {|e|p e}
     #-> Yields <b/>, <c/>, <d/>, <b/>, <c/>, <d/>
     XPath.each(doc.root, 'child::node()', &block)
     #-> Yields <b/>, <c/>, <d/>, sean, <b/>, <c/>, <d/>

size()

Returns the number of `Element` children of the parent object.

     doc = Document.new '<a>sean<b/>elliott<b/>russell<b/></a>'
     doc.root.size            #-> 6, 3 element and 3 text nodes
     doc.root.elements.size   #-> 3

to_a( xpath=nil )

Returns an Array of Element children. An XPath may be supplied to filter the children. Only Element children are returned, even if the supplied XPath matches non-Element children.

     doc = Document.new '<a>sean<b/>elliott<c/></a>'
     doc.root.elements.to_a                  #-> [ <b/>, <c/> ]
     doc.root.elements.to_a("child::node()") #-> [ <b/>, <c/> ]
     XPath.match(doc.root, "child::node()")  #-> [ sean, <b/>, elliott, <c/> ]