QGIS/resources/function_help/json/regexp_match

{
  "name": "regexp_match",
  "type": "function",
  "description": "Return the first matching position matching a regular expression within a string, or 0 if the substring is not found.",
  "arguments": [ {"arg":"input_string","description":"the string to test against the regular expression"},
  {"arg":"regex","description":"The regular expression to test against. Backslash characters must be double escaped (eg \"\\\\\\\\s\" to match a white space character)."}
  ],
  "examples": [ { "expression":"regexp_match('QGIS ROCKS','\\\\\\\\sROCKS')", "returns":"4"}]
}