int vertexattribsize(<geometry>geometry, string attribute_name)
When running in the context of a node (such as a wrangle SOP), this argument can be an integer representing the input number (starting at 0) to read the geometry from.
Alternatively, the argument can be a string specifying a geometry file (for example, a
.bgeo) to read from. When running inside Houdini, this can be an
See attribsize for more information.
0 if the attribute cannot be found.