DataFolderExists
DataFolderExists (dataFolderNameStr)
The DataFolderExists function returns the truth that the specified data folder exists.
dataFolderNameStr can be a full path or partial path relative to the current data folder.
If dataFolderNameStr is empty (""), DataFolderExists returns 1 because, for historical reasons, an empty data folder path is taken to refer to the current data folder.