REXML红宝石的下一个元素

Question

我正在尝试从XML获取元素和下一个元素

<way>
 <nd ref="4979923479"/>
 <nd ref="4979923478"/>
 <nd ref="5721236634"/>
 <nd ref="5721236635"/>
 <nd ref="5721236636"/>
 <nd ref="5721236637"/>
 <nd ref="4979923477"/>
 <nd ref="5721236638"/>
 <nd ref="5721236639"/>
</way>

这是我尝试做的事情，但是除了“ puts i.attributes [“ ref”]“”之外，我需要的是“ puts”＃{i.attributes [“ ref”]]}-> i.next（i +1）.attributes [“ ref”]

require "rexml/document"
include REXML
inputFileName = ARGV[0]
file = File.new(inputFileName)
doc = Document.new(file)

doc.elements.each("way/nd") do |i|
    if i.next != nil
        puts i.attributes["ref"]
    end
end

实际输出只是所有nd的列表

4979923479
4979923478
5721236634
5721236635
5721236636
5721236637
4979923477
5721236638
5721236639

所需的输出是：

4979923479 -> 4979923478
4979923478 -> 5721236634
5721236634 -> 5721236635
5721236635 -> 5721236636
5721236636 -> 5721236637
5721236637 -> 4979923477
4979923477 -> 5721236638
5721236638 -> 5721236639

Answer 1

我认为您想改用next_element。这样会产生所需的输出：

require "rexml/document"
include REXML
inputFileName = ARGV[0]
file = File.new(inputFileName)
doc = Document.new(file)

doc.elements.each("way/nd") do |i|
  next unless i.next_element
  puts "#{i.attributes["ref"]} -> #{i.next_element.attributes['ref']}"
end