XPath sorting not persistent?

Question

I have a following XML:

<doc>
<ActivityNarrativeInformation>
  <ActivityID>123456789</ActivityID>
  <ActivityNarrativeInformationID>111111111</ActivityNarrativeInformationID>
  <ActivityNarrativeSequenceNumber>1</ActivityNarrativeSequenceNumber>
  <ActivityNarrativeText>She Sells Sea Shells by the Sea Shore and she also</ActivityNarrativeText>
  </ActivityNarrativeInformation>
 <ActivityNarrativeInformation>
  <ActivityID>123456789</ActivityID>
  <ActivityNarrativeInformationID>111111111</ActivityNarrativeInformationID>
  <ActivityNarrativeSequenceNumber>3</ActivityNarrativeSequenceNumber>
  <ActivityNarrativeText>triple shot frappuccino, extra hot, with whipped cream in a tall cup </ActivityNarrativeText>
</ActivityNarrativeInformation>
<ActivityNarrativeInformation>
  <ActivityID>123456789</ActivityID>
  <ActivityNarrativeInformationID>111111111</ActivityNarrativeInformationID>
  <ActivityNarrativeSequenceNumber>2</ActivityNarrativeSequenceNumber>
  <ActivityNarrativeText>likes to take long walks on the beach while she drinks a</ActivityNarrativeText>
  </ActivityNarrativeInformation>
<ActivityNarrativeInformation>
  <ActivityID>987654321</ActivityID>
  <ActivityNarrativeInformationID>222222222</ActivityNarrativeInformationID>
  <ActivityNarrativeSequenceNumber>486</ActivityNarrativeSequenceNumber>
  <ActivityNarrativeText>It was a dark and stormy night; the rain fell in torrents--except at occasional intervals, when
 </ActivityNarrativeText>
</ActivityNarrativeInformation>
<ActivityNarrativeInformation>
  <ActivityID>987654321</ActivityID>
  <ActivityNarrativeInformationID>222222222</ActivityNarrativeInformationID>
  <ActivityNarrativeSequenceNumber>488</ActivityNarrativeSequenceNumber>
  <ActivityNarrativeText>scene lies), rattling along the housetops, and fiercely agitating the scanty flame of the lamps that
</ActivityNarrativeText>
</ActivityNarrativeInformation>
<ActivityNarrativeInformation>
  <ActivityID>987654321</ActivityID>
  <ActivityNarrativeInformationID>222222222</ActivityNarrativeInformationID>
  <ActivityNarrativeSequenceNumber>487</ActivityNarrativeSequenceNumber>
  <ActivityNarrativeText>was checked by a violent gust of wind which swept up the streets (for it is in London that our
</ActivityNarrativeText>
</ActivityNarrativeInformation>
<ActivityNarrativeInformation>
  <ActivityID>987654321</ActivityID>
  <ActivityNarrativeInformationID>222222222</ActivityNarrativeInformationID>
  <ActivityNarrativeSequenceNumber>489</ActivityNarrativeSequenceNumber>
  <ActivityNarrativeText>struggled against the darkness.
</ActivityNarrativeText>
</ActivityNarrativeInformation>
<ActivityNarrativeInformation>
  <ActivityID>55555555</ActivityID>
  <ActivityNarrativeInformationID>77777777</ActivityNarrativeInformationID>
  <ActivityNarrativeSequenceNumber>31921</ActivityNarrativeSequenceNumber>
  <ActivityNarrativeText>Papa Bear was very big and growly. Mamma Bear was middle-sized and pleasant.
</ActivityNarrativeText>
</ActivityNarrativeInformation>
<ActivityNarrativeInformation>
  <ActivityID>55555555</ActivityID>
  <ActivityNarrativeInformationID>77777777</ActivityNarrativeInformationID>
  <ActivityNarrativeSequenceNumber>31923</ActivityNarrativeSequenceNumber>
  <ActivityNarrativeText>Papa bear loved to fix things around the house; Mama bear loved to grow flowers in her garden; and, Baby bear loved playing in the yard. They were very happy. </ActivityNarrativeText>
</ActivityNarrativeInformation>
<ActivityNarrativeInformation>
  <ActivityID>55555555</ActivityID>
  <ActivityNarrativeInformationID>77777777</ActivityNarrativeInformationID>
  <ActivityNarrativeSequenceNumber>31920</ActivityNarrativeSequenceNumber>
  <ActivityNarrativeText>Once upon a time there were three bears, Papa Bear, Mamma Bear and Baby Bear
</ActivityNarrativeText>
</ActivityNarrativeInformation>
<ActivityNarrativeInformation>
  <ActivityID>55555555</ActivityID>
  <ActivityNarrativeInformationID>77777777</ActivityNarrativeInformationID>
  <ActivityNarrativeSequenceNumber>31922</ActivityNarrativeSequenceNumber>
  <ActivityNarrativeText>And Baby Bear, well, he was small, and
sometimes he squeaked! They lived in a pretty little house on the edge of the forest
</ActivityNarrativeText>
</ActivityNarrativeInformation>
</doc

I need to group ActivityNarrativeInformation elements by ActivityID and concatenate ActivityNarrativeText in such a way, that it is sorted by ActivityNarrativeSequenceNumber

I managed to sort elements with following XPath query (XPath 3.1) sort(//ActivityNarrativeInformation[ActivityID=123456789], (), function($ActivityNarrativeSequenceNumber) {$ActivityNarrativeSequenceNumber})

So the result looks like this:

<ActivityNarrativeInformation>
  <ActivityID>123456789</ActivityID>
  <ActivityNarrativeInformationID>111111111</ActivityNarrativeInformationID>
  <ActivityNarrativeSequenceNumber>1</ActivityNarrativeSequenceNumber>
  <ActivityNarrativeText>She Sells Sea Shells by the Sea Shore and she also</ActivityNarrativeText>
  </ActivityNarrativeInformation>
<ActivityNarrativeInformation>
  <ActivityID>123456789</ActivityID>
  <ActivityNarrativeInformationID>111111111</ActivityNarrativeInformationID>
  <ActivityNarrativeSequenceNumber>2</ActivityNarrativeSequenceNumber>
  <ActivityNarrativeText>likes to take long walks on the beach while she drinks a</ActivityNarrativeText>
  </ActivityNarrativeInformation>
<ActivityNarrativeInformation>
  <ActivityID>123456789</ActivityID>
  <ActivityNarrativeInformationID>111111111</ActivityNarrativeInformationID>
  <ActivityNarrativeSequenceNumber>3</ActivityNarrativeSequenceNumber>
  <ActivityNarrativeText>triple shot frappuccino, extra hot, with whipped cream in a tall cup </ActivityNarrativeText>
</ActivityNarrativeInformation>

The probelm however is, that if I want to limit down above to just all ActivityNarrativeText by adding /ActivityNarrativeText at the end like this

sort(//ActivityNarrativeInformation[ActivityID=123456789], (), function($ActivityNarrativeSequenceNumber) {$ActivityNarrativeSequenceNumber})/ActivityNarrativeText

or

sort(//ActivityNarrativeInformation[ActivityID=123456789]/ActivityNarrativeText, (), function($seq) {$seq/ActivityNarrativeSequenceNumber})

The order is lost:

<ActivityNarrativeText>She Sells Sea Shells by the Sea Shore and she also</ActivityNarrativeText>
<ActivityNarrativeText>triple shot frappuccino, extra hot, with whipped cream in a tall cup </ActivityNarrativeText>
<ActivityNarrativeText>likes to take long walks on the beach while she drinks a</ActivityNarrativeText>

What am I doing wrong?

score 2 · Answer 1 · answered Jul 04 '21 at 16:59

You lose the order when you write /ActivityNarrativeText, and it returns the <ActivityNarrativeText> in the same order they have in the input file

/something with nodes does not just mean map it to the child.

It means

Map it
Reorder all nodes to the input document order
Remove duplicates

You could use !ActivityNarrativeText

score 1 · Answer 2 · answered Jul 03 '21 at 15:44

1

If what you want to do is extract a coherenet sentece from your sample xml from that particular ActivityID, this expression

string-join(sort(//ActivityNarrativeInformation[ActivityID=123456789]/ActivityNarrativeText/concat(normalize-space()," "), (), function($ActivityNarrativeSequenceNumber) {$ActivityNarrativeSequenceNumber}))

should output

She Sells Sea Shells by the Sea Shore and she also likes to take long walks on the beach while she drinks a triple shot frappuccino, extra hot, with whipped cream in a tall cup

answered Jul 03 '21 at 15:44

Jack Fleeting

24,385
6
23
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Testing it here: https://www.videlibri.de/cgi-bin/xidelcgi, but still the results are as described, i.e. the order is incorrect – Macin Jul 03 '21 at 15:54
1

@Macin Interesting; I tried in Base-X and it worked, but now it seems it only works with that particular `ActivityID`, but not with the other two... Let me check further. – Jack Fleeting Jul 03 '21 at 16:20

Reino · Answer 3 · 2021-07-05T17:10:29.783

1

Testing it here: videlibri.de/cgi-bin/xidelcgi

If you're using xidel, then please add its tag. And maybe cmd for Windows, or bash for Unix as well.

~~I'm not too sure this can be done with XPath.~~ I believe you're better off using XQuery.

For the narrative with <ActivityID>123456789</ActivityID> you could do:

$ xidel -s input.xml --xquery '
  normalize-space(
    for $x in //ActivityNarrativeInformation
    where $x/ActivityID = 123456789
    order by $x/ActivityNarrativeSequenceNumber
    return
    $x/ActivityNarrativeText
  )
'

For all narratives I'd suggest:

$ xidel -s input.xml --xquery '
  for $narrative at $i in //ActivityNarrativeInformation
  group by $id:=$narrative/ActivityID
  count $i
  return (
    $i,
    normalize-space(
      for $seq in $narrative
      order by $seq/ActivityNarrativeSequenceNumber
      return
      $seq/ActivityNarrativeText
    )
  )
'
1
Once upon a time there were three bears, [...]
2
She Sells Sea Shells by the Sea Shore and [...]
3
It was a dark and stormy night; the rain [...]

Group by <ActivityID> first, then in another for-loop order the sentences by <ActivityNarrativeSequenceNumber>.

Update 2021-07-05; I forgot about XPath's !. In that case one for-loop is enough:

$ xidel -s input.xml --xquery '
  for $narrative at $i in //ActivityNarrativeInformation
  order by $narrative/ActivityNarrativeSequenceNumber
  group by $id:=$narrative/ActivityID
  count $i
  return (
    $i,
    normalize-space($narrative ! ActivityNarrativeText)
  )
'

edited Jul 05 '21 at 17:10

answered Jul 04 '21 at 11:53

Reino

3,203
1
13
21

How does normalize-space() work on a sequence here? normalize-space() is supposed to accept at most one string. When passing a sequence of strings to xidel's normalize-space() it appears to only act on the first string. Saxon and Zorba both, correctly, give a cardinality error. Is $narrative always going to have exactly one item in this example? – David Denenberg Jul 07 '21 at 12:31
1

@DavidDenenberg No, `$narrative` is a sequence. If `normalize-space()` with your `xidel` binary only returns the first string, then your binary is too old. `normalize-space()` accept sequences as input. That's at least how I interpret https://www.w3.org/TR/xpath-functions-31/#func-normalize-space. And a recent `xidel` build supports it. – Reino Jul 07 '21 at 23:59
Yes, it appears to be an older binary. I won't doubt whether recent versions of xidel support this, but it is an incorrect interpretation of the specification. Clearly shows "xs:string?" as the parameter (zero or one atomic strings). – David Denenberg Jul 08 '21 at 13:58
@DavidDenenberg: Xidel also gives an error in [standard XQuery mode](https://videlibri.de/cgi-bin/xidelcgi?&data=&=&extract=normalize-space((%22a%22%2C%22b%22))%0A%0A&=&input-format=auto&printed-node-format=text&output-format=adhoc&compatibility=Standard%20XQuery&dot-notation=off&extract-kind=xquery3.1&no-extended-strings=true&no-json=true&no-json-literals=true&only-json-objects=true&strict-type-checking=true&strict-namespaces=true&case-sensitive=true). But all type checking is disabled by default because then the query evaluation runs like 20% faster – BeniBela Jul 19 '21 at 11:57

score 1 · Accepted Answer · answered Jul 04 '21 at 21:25

In addition to the right answer not to use / after sorting but ! instead, one of your attempts would actually work if your sort function argument selected the right element as the sort key:

sort(//ActivityNarrativeInformation[ActivityID=123456789]/ActivityNarrativeText, (), function($text) {$text/../ActivityNarrativeSequenceNumber})

XPath sorting not persistent?

4 Answers4

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