Construct a new virtual directory that can be used to efficiently read and work with files within a file index table.
Also callable on Queries → query.to_directory(...)
Parameters:
file_id_variable : str, optional
The name of the variable in the table containing file ids. Only required if the table contains more than one fileId variable.
file_name_variable : str, optional
The name of the variable in the table containing the file name. If unspecified, will look for a variable file_name within the current table, or otherwise will use the file's original name.
