Method: REXML::XPath.first

Defined in:
lib/rexml/xpath.rb

.first(element, path = nil, namespaces = nil, variables = {}, options = {}) ⇒ Object

Finds and returns the first node that matches the supplied xpath.

element

The context element

path

The xpath to search for. If not supplied or nil, returns the first node matching ‘*’.

namespaces

If supplied, a Hash which defines a namespace mapping.

variables

If supplied, a Hash which maps $variables in the query to values. This can be used to avoid XPath injection attacks or to automatically handle escaping string values.

XPath.first( node )
XPath.first( doc, "//b"} )
XPath.first( node, "a/x:b", { "x"=>"http://doofus" } )
XPath.first( node, '/book/publisher/text()=$publisher', {}, {"publisher"=>"O'Reilly"})



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# File 'lib/rexml/xpath.rb', line 31

def XPath::first(element, path=nil, namespaces=nil, variables={}, options={})
  raise "The namespaces argument, if supplied, must be a hash object." unless namespaces.nil? or namespaces.kind_of?(Hash)
  raise "The variables argument, if supplied, must be a hash object." unless variables.kind_of?(Hash)
  parser = XPathParser.new(**options)
  parser.namespaces = namespaces
  parser.variables = variables
  path = "*" unless path
  element = [element] unless element.kind_of? Array
  parser.parse(path, element).flatten[0]
end