Determine Data Ranges in Excel Files

You can provide Excel cell ranges as input data to AIMMS AXLL functions. Here we show how to adapt when the ranges are unknown, for example, when end users upload Excel files as input in the AIMMS app.

We include a modified version of the exampleNFL project used in AIMMS Excel Library - AXLL.

Sufficiently large ranges

Provide a sufficiently large range and use the appropriate arguments to instruct AIMMS to traverse in the Excel file until it encounters an empty cell. For example, if you have set elements in “A2:A33” and corresponding parameter data in “D2:D33”, you can use the AXLL read procedures as shown below. If you are expecting empty cells in the set range, change the argument ‘SkipEmptyCells’ to 1 so that the entire range is traversed.

axll::ReadSet(
    SetReference              : sTeams ,
    SetRange                  : "A2:A50" ,
    ExtendSuperSets           :  1,
    MergeWithExistingElements :  0,
    SkipEmptyCells            :  0);

axll::ReadList(
    IdentifierReference    : spStadiumName ,
    RowHeaderRange         : "A2:A50" ,
    DataRange              : "D2:D50" ,
    ModeForUnknownElements :  0,
    MergeWithExistingData  :  0);

This works for most cases, but be aware:

  • if data extends beyond the large estimate provided, it is lost.

  • if two different data ranges are in the same column/row separated by empty cells or a header row, results are unreliable.

AXLL Functions

In AIMMS 4.70.4 and above, you have four new functions in the AXLL library to determine the boundaries of data in an Excel sheet. You can use these functions to find the last used row number or column number and coupled with other functions, you can construct the final cell range. For example, the code below will return spSetRange as “A2:A33” which you can then provide as an argument to axll::ReadSet.

If there is more data in a different column, then spSetRange will be a larger range than expected. That then becomes a case of using a sufficiently large range described in the previous section.

Similarly, axll::LastUsedColumnNumber will return the number of the last column in which there is data and you can use axll::ColumnName to convert it. For example, the below code will return spDataRange as “A2:AG33” in the Distances sheet:

pRowNum := axll::LastUsedRowNumber;
pColNum := axll::LastUsedColumnNumber;
axll::ColumnName(pColNum, spColName);
spDataRange := FormatString("A2:%s%n", spColName, pRowNum);

Like the previous method, using these functions is not straightforward if you have multiple data ranges in the same column/row separated by empty cells.

Named ranges

Another way is to create “Named Ranges” in the input Excel templates. You can then provide “NameofRange” as input to AXLL function arguments like ‘RowRange’ or ‘DataRange’ instead of “A2:A10”. However, the end user must update the named ranges if they add new rows or columns. A table name is automatically expanded but AXLL functions do not recognize Excel tables.

Other techniques

Other techniques to determine the consecutive ranges include:

  • Using axll::ReadSet with a sufficiently large range and using errh::Message() functions to retrieve the cell in which reading stopped from the warning message generated.

  • Using a while loop in combination with axll::ReadSingleValue and stop the loop when an empty cell is encountered.

To use existing functions and avoid custom procedures for data input, follow these guidelines:

  • Separate out data into different sheets based on the index domains of the corresponding AIMMS identifiers.

  • Don’t mix list-type data with matrix-type data.