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tutorials:xl-queries-and-operators [2024/12/07 16:27] – [Query examples] ksmolentutorials:xl-queries-and-operators [2025/06/02 07:36] (current) – added transitive closure examples ksmolen
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 } }
 </code> </code>
 +
 +{{ :tutorials:graph_query_example_2rot.png?200|}}
 +
 +The underlying 2d graph of the generated structure given below:
 +
 +Beginning from //RGGRoot//, we have the sequence of three //Internodes// where to each a //Leaf// is linked by a branching edge. The last internode, additionally, has a Bud node successor.
 +
  
 ==== Query examples ==== ==== Query examples ====
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 Aggregate operations are used to collect multiple values when traversing the graph structure and return a single value. Aggregate operations are used to collect multiple values when traversing the graph structure and return a single value.
  
-Standard [[groimp-platform:xl-operators|aggregate operations]] are: ''count'', ''sum'', ''empty'', ''exist'', ''forall'', ''first'', ''last'', ''max'', ''min'', ''mean'', ''selectRandomly'', ''selectWhereMin'', ''selectWhereMax'', ...+Standard [[:groimp-platform:xl-builtin-methods|aggregate operations]] are: ''count'', ''sum'', ''empty'', ''exist'', ''forall'', ''first'', ''last'', ''max'', ''min'', ''mean'', ''selectRandomly'', ''selectWhereMin'', ''selectWhereMax'', ...
  
   * Count all leaves:    * Count all leaves: 
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 count((* Leaf *)) count((* Leaf *))
 </code> </code>
 +
 +<hidden answer>
 +3
 +</hidden>
 +
  
   * Sum up the area of all leaves:   * Sum up the area of all leaves:
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 sum((* Leaf *)[area]) sum((* Leaf *)[area])
 </code> </code>
 +
 +<hidden answer>
 +6.0
 +</hidden>
 +
  
   * Sum up the length of internodes:   * Sum up the length of internodes:
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 sum((* Internode *)[length]) sum((* Internode *)[length])
 </code> </code>
 +
 +<hidden answer>
 +6.0
 +</hidden>
  
 In this particular example with internodes forming (only) the main stem, the query will return stem length. In this particular example with internodes forming (only) the main stem, the query will return stem length.
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 selectWhereMax((* l:Leaf *), (l[area])) selectWhereMax((* l:Leaf *), (l[area]))
 </code> </code>
 +
 +<hidden answer>
 +Model.Leaf[id=1903]@668c1f97
 +</hidden>
 +
  
   * Count internodes that are older than 2 (time units):   * Count internodes that are older than 2 (time units):
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 </code> </code>
  
 +<hidden answer>
 +2
 +</hidden>
 +
 +==== Transitive closure ====
 +
 +Transitive closure is a concept used to derive relations between successive nodes connected by several edges of the same type. For example, we want to find all descendants of some given node that are of type Internode.
 +
 +The quantifier ''+'' stands for 1-to-//n// repetitions, the quantifier ''*'' stands for 0-to-//n// repetitions.
 +
 +  * Find all internodes connected to the bud:
 + 
 +<code java> 
 +(* Bud (<--)+ Internode *)
 +</code>
 +
 +Special syntax is used after the quantifier if we are interested only in finding minimal elements '':(node_type)'' 
 +
 +  * Find the first internode connected to the bud:
 + 
 +<code java> 
 +(* Bud (<--)+ :(Internode) *)
 +</code>
tutorials/xl-queries-and-operators.1733585279.txt.gz · Last modified: 2024/12/07 16:27 by ksmolen