method

first

v1_9_3_392 - Show latest stable - 0 notes - Class: REXML::XPath

first(element, path=nil, namespaces=nil, variables={}) public

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"})

Show source

# File lib/rexml/xpath.rb, line 30
    def XPath::first element, path=nil, namespaces=nil, variables={}
      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
      parser.namespaces = namespaces
      parser.variables = variables
      path = "*" unless path
      element = [element] unless element.kind_of? Array
      parser.parse(path, element).flatten[0]
    end

first

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