To construct a list in SPARQL, you can use the values
keyword followed by a list of variables and values enclosed in curly brackets {}. Each set of values represents a single element in the list. You can then query the list using the values
keyword in your SELECT statement to retrieve the elements of the list as distinct rows in the result set. Lists can be used to represent collections of data or to pass multiple values as input parameters to a query.
How to find the union of two lists in SPARQL?
You can find the union of two lists in SPARQL by using the UNION operator. The UNION operator is used to combine the results of two separate SELECT queries into a single result set. Here is an example of how to find the union of two lists in SPARQL:
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SELECT ?item WHERE { { ?item a <http://example.org/class1> . } UNION { ?item a <http://example.org/class2> . } } |
In this example, the query will return all items that are either of type <http://example.org/class1>
or <http://example.org/class2>
. The UNION operator allows you to merge the results of two separate queries into a single result set.
What is the function of the cons operator in SPARQL lists?
In SPARQL, the cons operator is used to add an element to the front of a list. It takes two arguments: the element to be added and the existing list. The cons operator results in a new list where the element is added to the front of the existing list.
What is a list in SPARQL?
In SPARQL, a list is a sequence of values enclosed in square brackets ([]), separated by commas. Lists can be used to group together multiple values or elements within a query for processing or filtering. Lists can contain literals, URIs, or variables, and can be used in various parts of a SPARQL query, such as in the VALUES clause, as an argument in a function, or as a collection in a filter condition.