How To - Read and Write CSV Files (updated)

Hi,

I’m new to AIMMS and I’m trying to read multiple csv files with the file name dynamically updates.

I created a procedure as follows:

Empty data_declarations ;

SetElementAdd(S_datatable, EP_datatable, SP_filename);

dl::DataTables := S_datatable ;

DataMap(dl::dt,dl::idn,dl::cn,dl::dn) :=  data {
	( S_datatable, sLocs, 1, 1 ) : "location",
	( S_datatable, sProd, 2, 2 ) : "product",
	( S_datatable, pDem , 3, 0 ) : "demand", 
	( S_datatable, spCmt, 4, 0 ) : "comment"
};
dl::RemoveDataSourceMapping("TheMapping");
dl::AddDataSourceMapping("TheMapping", DataMap, dl::DependEmpty, dl::TableAttributesEmpty, dl::ColAttributeEmpty);

spCommunicationAttributes := 
      { 'DataProvider' : csvprov::DataLink , 
        'ContainsHeaders' : "yes"
        ! Note that Separator attribute is left to its default of ",".
      };

dl::DataRead("komma",                 ! reading from data source "komma" - because we use csvprovider this data source is a folder.
        "TheMapping" ,                ! using relation "TheMapping" between folder komma and AIMMS identifiers.
        spCommunicationAttributes);   ! Technicalities on how to communicate.

Also I created a set and string parameter as instructed by tutorial.
 

Set S_datatable {
    SubsetOf: dl::DataTables;
    Parameter: EP_datatable;
}

StringParameter SP_filename;

But when I run the procedure, it gives me the following error:

The element S_datatable is not in the range set of the running index dt.

Can you please help resolve this issue.

Thanks