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Thread: Regular Expression To Catch Duplicates

  1. #1
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    Default Regular Expression To Catch Duplicates

    I want to know how to use "matches()" to catch when a duplicate appears in my String "xmlString" (which contains an xml file).

    So for example the following fragment should return "false":

    <Countries>
    <Country>BE</Country>
    <Country>DE</Country>
    <Country>GB</Country>
    </Countries>

    Whereas the following fragment should return "true":

    <Countries>
    <Country>BE</Country>
    <Country>DE</Country>
    <Country>GB</Country>
    <Country>DE</Country>
    </Countries>

    So far my comparison looks like this:

    boolean containsDuplicateCountry = xmlString.matches(".*<Country>[A-Z]{2}</Country>.*");

    which just returns "true" for any upper case 2 digit territory code. I have no idea how to amend this to check for a duplicate. Any ideas would be really appreciated. Thanks,

    Daniel


  2. #2
    Super Moderator copeg's Avatar
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    Default Re: Regular Expression To Catch Duplicates

    Parse and capture each value using a Pattern/Matcher and use a a Set to check for duplicates.
    Lesson: Regular Expressions (The Java™ Tutorials > Essential Classes)
    The Set Interface (The Java™ Tutorials > Collections > Interfaces)

  3. The Following User Says Thank You to copeg For This Useful Post:

    daniel_el (February 9th, 2012)

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