re = /(Order[0-9])(?!.*\1)/
str = '<ctx>
<PostCode>XXXXXX</PostCode>
<Title1>Mr</Title1>
<Name>John</Name>
<Order1>£100.00</Order1>
<Order2>£100.01</Order2>
<Order3>£100.01</Order3>
<Order4>£100.01</Order4>
<Order5>£100.01</Order5>
<Order6>£100.01</Order6>
<Order7>£100.01</Order7>
<Order8>£100.01</Order8>
<Order9>£100.01</Order9>
<Order10>£100.01</Order10>
<Order11>£100.01</Order11>
<Order50>£100.01</Order50>
<Date>10/10/2010</Date>
</ctx>'
# Print the match result
str.scan(re) do |match|
puts match.to_s
end
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for Ruby, please visit: http://ruby-doc.org/core-2.2.0/Regexp.html