Re: XQuery/XPath 3.1: Node List to Node Set ("distinct

To see that the original sequence order is preserved in the result, here is
a complete example:

let $xml := parse-xml("<t><a/><b/><c/></t>"),
    $nodes := ($xml/*/a, $xml/*/c, $xml/*/b, $xml/*/a, $xml/*/b ),
    $ids := distinct-values($nodes ! generate-id(.))
 return  $ids ! (function($id) {$nodes[generate-id(.) eq $id][1]})(.)

produces:

<a/>
<c/>
<b/>



On Tue, Dec 28, 2021 at 3:32 PM Dimitre Novatchev dnovatchev@xxxxxxxxx <
xsl-list-service@xxxxxxxxxxxxxxxxxxxxxx> wrote:

>
>
> On Tue, Dec 28, 2021 at 3:29 PM Dimitre Novatchev <dnovatchev@xxxxxxxxx>
> wrote:
>
>> A pure XPath solution:
>>
>> let $ids := distinct-values($nodes ! generate-id(.))
>>    return  $ids ! (function($id) {$nodes[generate-id(.) eq $id][1]})(.)
>>
>> Happy New Year to all !
>>
>
>
> Hit Send too early:
>
> Do notice: this seems the only solution of all presented so far, that
> preserves the original sequence order (not document order) of the nodes.
>
>
>
>>
>> On Tue, Dec 28, 2021 at 2:39 PM Wendell Piez wapiez@xxxxxxxxxxxxxxx <
>> xsl-list-service@xxxxxxxxxxxxxxxxxxxxxx> wrote:
>>
>>> Eliot and XSL-List,
>>>
>>> Along similar lines to $nodes | (), consider
>>>
>>> $nodes except ()
>>> $nodes intersect $nodes
>>>
>>> I'm finding it difficult to argue what's most intuitive but I kind of
>>> like 'intersect'. Can't vouch for performance though. :-)
>>>
>>> Best wishes for 2022 --
>>> Wendell
>>>
>>>
>>>
>>>
>>> On Tue, Dec 28, 2021 at 4:56 PM Michael Kay mike@xxxxxxxxxxxx <
>>> xsl-list-service@xxxxxxxxxxxxxxxxxxxxxx> wrote:
>>>
>>>> You might consider
>>>>
>>>> $nodes | ()
>>>>
>>>> a bit more intuitive.
>>>>
>>>> Michael Kay
>>>> Saxonica
>>>>
>>>> On 28 Dec 2021, at 19:23, Eliot Kimber eliot.kimber@xxxxxxxxxxxxxx <
>>>> xsl-list-service@xxxxxxxxxxxxxxxxxxxxxx> wrote:
>>>>
>>>> Hmph.
>>>>
>>>> That is certainly much more efficient p
 but is not necessarily
>>>> obvious (at least not to me).
>>>>
>>>> Thanks!
>>>>
>>>> E.
>>>>
>>>> _____________________________________________
>>>> *Eliot Kimber*
>>>> Sr Staff Content Engineer
>>>> O: 512 554 9368
>>>>
>>>> M: 512 554 9368
>>>> servicenow.com <https://www.servicenow.com/>
>>>> LinkedIn <https://www.linkedin.com/company/servicenow> | Twitter
>>>> <https://twitter.com/servicenow> | YouTube
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>>>>
>>>>
>>>> *From: *Martin Honnen martin.honnen@xxxxxx <
>>>> xsl-list-service@xxxxxxxxxxxxxxxxxxxxxx>
>>>> *Date: *Tuesday, December 28, 2021 at 1:15 PM
>>>> *To: *xsl-list@xxxxxxxxxxxxxxxxxxxxxx <xsl-list@xxxxxxxxxxxxxxxxxxxxxx>
>>>> *Subject: *Re:  XQuery/XPath 3.1: Node List to Node Set
>>>> ("distinct nodes")
>>>>
>>>> [External Email]
>>>>
>>>>
>>>> On 28.12.2021 20:10, Eliot Kimber eliot.kimber@xxxxxxxxxxxxxx wrote:
>>>> > I couldnbt find an answer in my google and markmail searching so I
>>>> > thought Ibd ask here:
>>>> >
>>>> > Given an arbitrary list of nodes that may contain duplicates, what is
>>>> > the most efficient way to reduce the node list to a set?
>>>> >
>>>> > The solution I came up with is a recursive function:
>>>> >
>>>> > (:
>>>> >
>>>> > Get the unique nodes from the supplied sequence
>>>> >
>>>> > @param nodes The sequence of nodes to evaluate
>>>> >
>>>> > @return A sequence of nodes such that each node in $nodes exists
>>>> exactly
>>>> > once.
>>>> >
>>>> > :)
>>>> >
>>>> > declare function dutils:distinctNodes($nodes as node()*) as node()* {
>>>> >
>>>> >    dutils:_getDistinctNodes($nodes, ())
>>>> >
>>>> > };
>>>> >
>>>> > declare function dutils:_getDistinctNodes($nodes as node()*,
>>>> $resultList
>>>> > as node()*) as node()* {
>>>> >
>>>> >    if (exists($nodes))
>>>> >
>>>> >    then
>>>> >
>>>> >    let $node := head($nodes)
>>>> >
>>>> >    return dutils:_getDistinctNodes(tail($nodes), ($resultList |
>>>> $node))
>>>> >
>>>> >    else $resultList
>>>> >
>>>> > };
>>>> >
>>>> > Which works but I feel like Ibm missing some obvious way to do this
>>>> more
>>>> > directly, but Ibm not seeing it.
>>>> >
>>>> > Am I missing a better solution?
>>>>
>>>> $nodes/.
>>>> XSL-List info and archive <http://www.mulberrytech.com/xsl/xsl-list>
>>>> EasyUnsubscribe <http://lists.mulberrytech.com/unsub/xsl-list/293509>
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>>>>
>>>>
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>>>>
>>>
>>>
>>> --
>>> ...Wendell Piez... ...wendell -at- nist -dot- gov...
>>> ...wendellpiez.com... ...pellucidliterature.org... ...pausepress.org...
>>> ...github.com/wendellpiez... ...gitlab.coko.foundation/wendell...
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>>> email)
>>>
>>
>>
>> --
>> Cheers,
>> Dimitre Novatchev
>> ---------------------------------------
>> Truly great madness cannot be achieved without significant intelligence.
>> ---------------------------------------
>> To invent, you need a good imagination and a pile of junk
>> -------------------------------------
>> Never fight an inanimate object
>> -------------------------------------
>> To avoid situations in which you might make mistakes may be the
>> biggest mistake of all
>> ------------------------------------
>> Quality means doing it right when no one is looking.
>> -------------------------------------
>> You've achieved success in your field when you don't know whether what
>> you're doing is work or play
>> -------------------------------------
>> To achieve the impossible dream, try going to sleep.
>> -------------------------------------
>> Facts do not cease to exist because they are ignored.
>> -------------------------------------
>> Typing monkeys will write all Shakespeare's works in 200yrs.Will they
>> write all patents, too? :)
>> -------------------------------------
>> Sanity is madness put to good use.
>> -------------------------------------
>> I finally figured out the only reason to be alive is to enjoy it.
>>
>>
>
>
> --
> Cheers,
> Dimitre Novatchev
> ---------------------------------------
> Truly great madness cannot be achieved without significant intelligence.
> ---------------------------------------
> To invent, you need a good imagination and a pile of junk
> -------------------------------------
> Never fight an inanimate object
> -------------------------------------
> To avoid situations in which you might make mistakes may be the
> biggest mistake of all
> ------------------------------------
> Quality means doing it right when no one is looking.
> -------------------------------------
> You've achieved success in your field when you don't know whether what
> you're doing is work or play
> -------------------------------------
> To achieve the impossible dream, try going to sleep.
> -------------------------------------
> Facts do not cease to exist because they are ignored.
> -------------------------------------
> Typing monkeys will write all Shakespeare's works in 200yrs.Will they
> write all patents, too? :)
> -------------------------------------
> Sanity is madness put to good use.
> -------------------------------------
> I finally figured out the only reason to be alive is to enjoy it.
>
> XSL-List info and archive <http://www.mulberrytech.com/xsl/xsl-list>
> EasyUnsubscribe <http://lists.mulberrytech.com/unsub/xsl-list/782854> (by
> email <>)
>


--
Cheers,
Dimitre Novatchev
---------------------------------------
Truly great madness cannot be achieved without significant intelligence.
---------------------------------------
To invent, you need a good imagination and a pile of junk
-------------------------------------
Never fight an inanimate object
-------------------------------------
To avoid situations in which you might make mistakes may be the
biggest mistake of all
------------------------------------
Quality means doing it right when no one is looking.
-------------------------------------
You've achieved success in your field when you don't know whether what
you're doing is work or play
-------------------------------------
To achieve the impossible dream, try going to sleep.
-------------------------------------
Facts do not cease to exist because they are ignored.
-------------------------------------
Typing monkeys will write all Shakespeare's works in 200yrs.Will they write
all patents, too? :)
-------------------------------------
Sanity is madness put to good use.
-------------------------------------
I finally figured out the only reason to be alive is to enjoy it.