[xquery-talk] find most occurring incidence

[Christian Grün]

And two another solutions, taking advantage of maps:

The more readable one:

  let $map := map:merge(
    for $color in //color
    group by $value := $color
    return map { $value: count($color) }
  )
  let $max := max($map?*)
  return map:for-each($map, function($color, $value) {
    if($value eq $max) then $color else ()
  })

The more cryptical (and not that efficient) one:

  let $m := map:merge(
    for $v in distinct-values(//color)
    return map { $v: count(//color[. eq $v]) }
  )
  return map:keys($m)[$m(.) = max($m?*)]



On Tue, Apr 26, 2016 at 12:17 PM, Christian Grün
<christian.gruen at gmail.com> wrote:
> Hi Leo,
>
> here’s one more solution. It is not much shorter than yours, but may
> be a bit more readable:
>
>   let $cols :=
>     for $colors in //color
>     group by $value := $colors/data()
>     return <color count="{ count($colors) }" value="{ $value }"/>
>   let $max := max($cols/@count)
>   return $cols[@count = $max]/@value/data()
>
> I think that in every case the values need to be accessed at least
> twice, because we’ll first need to find out what is the actual maximum
> count, and then need to look for all values matching that maximum.
>
> Hope this helps,
> Christian
>
>
>
> On Tue, Apr 26, 2016 at 12:02 PM, Leo Studer <leo.studer at varioweb.ch> wrote:
>> Hello Cracks ;-)
>>
>> I need to find the most occurring incidence, lets say the color that occurs
>> most out of
>>
>> <colors>
>>     <color>red</color>
>>     <color>green</color>
>>     <color>blue</color>
>>     <color>red</color>
>>     <color>green</color>
>>     <color>green</color>
>>     <color>red</color>
>>     <color>blue</color>
>>    <!-- .... -->
>> </colors>
>>
>>
>> Here my first solution
>>
>> (for $color in distinct-values(//color)
>> order by count(//color[. eq $color]) descending
>> return $color)[1]
>>
>> Problem: red and green have both 3 occurrences.
>>
>> This works but looks horrible
>>
>> for $max in max(for $color in distinct-values(//color) return
>> count(//color[. eq $color])),
>> $color in distinct-values(//color)
>> return
>> if (count(//color[. eq $color]) eq $max) then $color else ()
>>
>>
>> Any better suggestions?
>>
>> Thanks in advance
>> Leo
>>
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