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2 min readTo 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.
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5 min readTo filter distinct regex matches with SPARQL, you can use the DISTINCT keyword in combination with a regular expression filter. This allows you to retrieve only unique results that match the given pattern. You can achieve this by using the FILTER clause in your SPARQL query along with the regular expression function REGEX.For example, you can filter distinct matches for a specific pattern in the ?label attribute of a resource by using the following query: SELECT DISTINCT ?resource .
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4 min readTo iterate over a list in SPARQL, you can use the VALUES clause to specify a list of items that need to be iterated. This allows you to work with multiple values at once in a single query. You can also use the UNION operator to combine the results of multiple queries into a single result set. Additionally, you can use the FILTER keyword to further refine the results based on certain conditions.
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7 min readTo specify a specific class in SPARQL, you can use the "a" keyword followed by the name of the class you want to specify. For example, if you want to specify that a resource is of type "Person", you can use the following syntax in your SPARQL query:?person a :Person .This will specify that the resource represented by the variable "?person" is of type "Person".
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3 min readIn SPARQL, you can get today's date by using the built-in function NOW(). This function returns the current date and time in the format YYYY-MM-DDTHH:MM:SS. To extract only the date part, you can use the STRDT() and DATE() functions. Here is an example query to get today's date:SELECT (STRDT(DATE(NOW()), xsd:date) AS ?today) WHERE {your query here}[rating:a23f4a27-36f7-419b-8202-45e21c7afb2c]What is the key technique for accessing today's date in SPARQL.
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6 min readTo add external variables to a SPARQL query, you need to use the BIND keyword followed by the variable assignment. You can use the BIND keyword to assign a value to a variable before executing the query. This allows you to use external variables in combination with the SPARQL query to retrieve specific results based on the assigned values. By binding external variables to the query, you can customize the results based on the input values provided.
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4 min readWhen dealing with duplicate specific values in a SPARQL query, one approach is to use the DISTINCT keyword to ensure that only unique values are returned in the results. This can be particularly useful when querying a dataset that may contain duplicate entries for a given property or value.
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6 min readTo run INSERT SPARQL queries from R, you can use the SPARQL package in R. First, you need to establish a connection to your SPARQL endpoint using the SPARQL function. Then, you can use the SPARQL function again to send your INSERT queries to the SPARQL endpoint. Make sure to enclose your SPARQL query within a triple-quoted string to avoid syntax errors. Finally, you can execute your query using the SPARQL function with the query argument set to your INSERT query.
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7 min readIn SPARQL, conditions within a single query can be applied using the FILTER keyword. This keyword allows you to specify conditions that should be met in order for a particular result to be included in the query results. Conditions can be based on equality or inequality of values, comparison of numeric values, or checking for the presence of a certain value in a property value.
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5 min readTo generate a SPARQL query to extract the publisher type, you will first need to identify the dataset or knowledge graph that contains the information about publishers. Once you have identified the dataset, you can write a SPARQL query that selects the publisher type for each publisher entity.The query will typically involve selecting the publisher entities and then selecting the type property for each publisher entity.
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3 min readIn SPARQL, you can set the language of a literal variable using the LANG() function. This function takes a string literal as its argument and returns the language tag associated with that literal. For example, if you have a variable ?label that contains a string literal "Hello" with the language tag "en" (for English), you can use the expression LANG(?label) to retrieve the language tag "en".