QGIS/resources/function_help/json/num_geometries

{
  "name": "num_geometries",
  "type": "function",
  "description": "Returns the number of geometries in a geometry collection, or null if the input geometry is not a collection.",
  "arguments": [ {"arg":"geometry","description":"geometry collection"} ],
  "examples": [ { "expression":"num_geometries(geom_from_wkt('GEOMETRYCOLLECTION(POINT(0 1), POINT(0 0), POINT(1 0), POINT(1 1))'))'),3))", "returns":"4"}]
}