| Operator Type: | Function |
| Operator Scope of Action: | Group |
| Operator Purpose: | List creation |
collect(group,attribute)
A function collect() builds a List (prior to v5.6.0 it was a Set) by visiting each note described by group and adding the value of the designated attribute to the set. See collect_if() for a related new operator.
group may be any of {children,descendants,siblings,ancestors,all}. In addition, group may be argument that designates a particular (single) note other than this.
attribute can be any expression, but is typically an attribute.
For example,
collect(children,$Name)
constructs a set with the name of each child of the note.
For example,
collect(children(/agents/books),$Name)
does the same for children of the note 'books' inside 'agents'.
collect(children,$Width * $Height)
collects a series of numerical values of each child's map icon height/width in Tinderbox map units. Thus if a child had a $Width of 4 and $Height of 2, the collect() result for that item would be 8.
If a list of unique values is required - i.e. a set rather than a list, simply pass the output to a Set attribute. Thus if:
$MyList = collect(children,$FavFruit) $MyList is "Apples;Oranges;Pears;Apples"
$MySet = collect(children,$FavFruit) MySet is "Apples;Oranges;Pears;"
