Splitting a comma separated string with regex in sparql

Question

i have to make a question about regex() in SPARQL. I would like to replace a variable, which sometime contains a phrase with a comma, with another that contains just what is before the comma. For example if the variable contains "I like it, ok" i want to get a new variable which contains "I like it". I don't know which regular expresions to use.

Answer 1

This is a use case for strbefore, you don't need regex at all. As a general tip, I suggest reading (or skimming) through the table of contents for Section 17 of the SPARQL 1.1 Query Language Recommendation. It lists all the SPARQL functions, and while you don't need to memorize them all, you'll at least have an idea of what's out there. (This is good advice for all programmers and languages: skim the table of contents and the index.) This query¹ shows how to use strbefore:

select ?x ?prefix where { 
  values ?x { "we invited the strippers, jfk and stalin" }
  bind( strbefore( ?x, "," ) as ?prefix )
}

---------------------------------------------------------------------------
| x                                          | prefix                     |
===========================================================================
| "we invited the strippers, jfk and stalin" | "we invited the strippers" |
---------------------------------------------------------------------------

---

^{1. See Strippers, JFK, and Stalin Illustrate Why You Should Use the Serial Comma}