very good Richard, thank you. I was working along these lines with the following
BIND (REPLACE(STR(?url),"[a-zA-Z0-9._-]+@[a-zA-Z0-9._-]+","$0") AS ?email) where ?url contains the match but binds the entire string again to ?email eg data: url = http://www.imagesnippets.com/imgtag/rdf/apple97...@hotmail.com/1598550_10204479279247862_1280347905880818932_o query SELECT ?email WHERE { ?s ?p ?o BIND (REPLACE(STR(?s),"[a-zA-Z0-9._-]+@[a-zA-Z0-9._-]+","$0") AS ?email) } On Tue, Apr 23, 2019 at 6:00 PM Richard Cyganiak <rich...@cyganiak.de> wrote: > > Hi Marco, > > > On 23 Apr 2019, at 15:53, Marco Neumann <marco.neum...@gmail.com> wrote: > > > > I think I'm familiar with functions on strings in SPARQL but as far as > > I can see there is nothing similar to a grep like pattern matching and > > extraction on strings for SPARQL. Or is there one? > > The replace function does pattern matching and allows extraction of matched > sub-patterns: > https://www.w3.org/TR/sparql11-query/#func-replace > <https://www.w3.org/TR/sparql11-query/#func-replace> > https://www.w3.org/TR/xpath-functions/#func-replace > <https://www.w3.org/TR/xpath-functions/#func-replace> > > replace(input, pattern, replacement) > > The special “variables” $1, $2, $3, and so on can be used in the replacement > string. They refer to parts of the input that were matched by the first, > second, third, and so on pair of parentheses in the regex pattern. For > example: > > replace("23 April 2019", "^([0-9][0-9])", "$1") > > would return "23" because that is the part of the input matched by the first > (and only) pair of parentheses. > > Also useful might be Jena’s own apf:strSplit property function: > https://jena.apache.org/documentation/query/library-propfunc.html > <https://jena.apache.org/documentation/query/library-propfunc.html> > > It can split a literal into multiple literals based on a regular expression. > > Taken together, these two functions can do a wide range of pattern matching > and extraction tasks. > > Hope that helps, > Richard -- --- Marco Neumann KONA
