Re: XPath string comparison of two strings representin

The values are not directly parseable as xs:date or xs:dateTime values, so I
think youbll have to preprocess them to make proper date strings out of them
and compare them as dates(), e.g.:

local:makeDate(/Test/Date2) gt local:makeDate(/Test/Date1)

Where I leave local:makeDate() as an exercise to the reader (

Cheers,

Eliot
--
Eliot Kimber
http://contrext.com



On 8/16/17, 11:09 AM, "Costello, Roger L. costello@xxxxxxxxx"
<xsl-list-service@xxxxxxxxxxxxxxxxxxxxxx> wrote:

    Hi Folks,

    I have an XML document that contains two elements with values representing
calendar dates, in YYYYMMDD format, e.g.,

    <Test>
        <Date1>20170816</Date1>
        <Date2>20170817</Date2>
    </Test>

    This is the format that iCalendar (RFC 5545) uses to represent dates.

    I wish to test to see if the calendar date represented in <Date2> is
greater than (occurs later in chronological time) the calendar date
represented in <Date1>. Here's an XPath expression to do the test:

    /Test/Date2 gt /Test/Date1

    In this case, the XPath returns true.

    Note that I am doing mere string comparison. I am comparing the string
'20170817' against the string '20170816'.

    Will the XPath always work?

    Is there a counterexample, where <Date2> holds a value representing a
calendar date that is less than (occurs earlier in chronological time) the
calendar date represented in <Data1>, and yet the XPath returns true?

    If there is a counterexample, what XPath expression will always work?

    /Roger