Or, retweeked and made for multiple maps (@ Marc thanx for the inspiration)
declare function XQR.map:merge
( $mapSet as map(*)*
, $mergeFunction as function(*)
) as map(*)
{
fold-left( $mapSet
, map {}
, function( $targetMap
, $sourceMap
)
{
map:merge(( $targetMap
, $sourceMap
, for-each( map:keys( $targetMap)[ . = map:keys( $sourceMap)]
, function( $key
)
{
map:entry( $key
, $mergeFunction( map:get( $targetMap, $key)
, map:get( $sourceMap, $key)
)
)
}
)
))
}
)
} ;
Use:
xqr.map:merge( ( map { 'a' : ( 1,2,3,4)
, 'b' : ( 4,5,6,7)
}
, map { 'b' : ( 6,7,8,9)
, '7' : ( 'x', 'y', 'z')
}
, map { 'b' : ( 9,10,12)
, '7' : ( 'x', 'y', 'p')
}
)
, function( $data1
, $data2
)
{
distinct-values(( $data1, $data2))
}
) ! map:serialize( .)
You’re welcome,
Rob
Van: basex-talk-bounces@mailman.uni-konstanz.de [mailto:basex-talk-bounces@mailman.uni-konstanz.de] Namens Graydon Saunders
Verzonden: woensdag 15 juli 2015 20:01
Aan: BaseX
Onderwerp: [basex-talk] Union of maps?
Hi --
In BaseX 8.2.1, I have a bunch of maps; the maps may have some overlap of key values. I would like to merge/find the union of all of these maps while retaining all the values associated with each key in the resulting map-of-all-maps. (Combined map? Any word can be wrong, here! :)
map:merge() doesn't do this; http://docs.basex.org/wiki/Map_Module#map:merge says
"The associated value for each such key is taken from the last map in the input sequence
$inputthat contains an entry with this key." and testing confirms this.
Is there a straightforward way to do this that I'm missing?
Thanks!
Graydon
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