QGIS/resources/function_help/json/num_geometries

{
  "name": "num_geometries",
  "type": "function",
  "groups": ["GeometryGroup"],
  "description": "Returns the number of geometries in a geometry collection, or the number of parts in a multi-part geometry. The function returns NULL if the input geometry is not a collection.",
  "arguments": [{
    "arg": "geometry",
    "description": "geometry collection or multi-part geometry"
  }],
  "examples": [{
    "expression": "num_geometries(geom_from_wkt('GEOMETRYCOLLECTION(POINT(0 1), POINT(0 0), POINT(1 0), POINT(1 1))'))",
    "returns": "4"
  },{
    "expression": "num_geometries(geom_from_wkt('MULTIPOINT((0 1), (0 0), (1 0))'))",
    "returns": "3"
  }],
  "tags": ["collection", "multipart", "parts", "count"]
}