Functions To Read Excel Worksheets

Revision as of 21:38, 28 July 2009 by Lchrisman (talk | contribs) (New names for spreadsheet functions, new to 4.2.0.21, plus sheet parameter moved to end in SpreadsheetSetRange)


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The functions described on this page allow you to easily retrieve results directly from an existing Excel spreadsheet. These can be used as an alternative to OLE linking or ODBC, which are two other methods for retrieving data from spreadsheets. They are introduced on an experimental basis in Analytica 4.1, and are only available from the Enterprise edition (or higher). They may be also used from ADE.

When you use these functions to query a spreadsheet, the values are obtained when the functions are evaluated, but no dependencies are maintained from the original data. Thus, if the data is changed in the spreadsheet, the Analytica results do not automatically invalidate, as occurs when OLE linking is used. Unless you have done something special to copy the values in your model, your results will be re-evaluated if a model is re-loaded at a later time, so that each time you start your model, you will be getting the most up-to-date data from the spreadsheet.

These functions provide access only to the computed results in a spreadsheet, but can be used to access the contents of arbitrary cells or named ranges, regardless of how the spreadsheet is laid out. The functions described here only provide read-access to the spreadsheet cells.

See also Functions to Write Data to Excel Worksheets.

<a name="SpreadsheetOpen" />

SpreadsheetOpen( filename, showDialog )

Opens the Excel file at the indicated filename and returns a special Workbook object, which displays in an Analytica result table as <<ExcelWorkbook>>.

The filename parameter is relative to the CurrentDataDirectory.

If you set showDialog to true, it will display a file dialog, even if the file filename exists. If showDialog is false (the default), it will display the dialog only if it does not find the file (the same behavior as ReadTextFile).

The filename can also accept a workbook name that is current open in Excel, even if it is not yet saved.

Example

SpreadsheetOpen( "C:\MyModels\Sales Numbers.xls" ) → «ExcelWorkbook»

<a name="SpreadsheetCell" />

SpreadsheetCell( workbook, sheet, column, row )

Reads the contents of one cell of a worksheet given its coordinates. The function fully array abstracts, so you use to read a range of cells by specifying the column and/or row as arrays.

Parameters:

  • workbook: A workbook object returned by SpreadsheetOpen
  • sheet: The name of a worksheet inside the workbook, or its number, where 1 is the first worksheet, etc.
  • column: The column label, e.g., "A", "B", or "AB", or the column number as an integer.
  • row: The row number

If the worksheet cell is empty, it returns Null. It flags an error if «workbook» is not a valid workbook, if it does not contain «sheet», or if the coordinates are invalid.

If you change the cell after evaluating a variable that uses SpreadsheetCell(), it has no effect, unless and until you recompute the variable. Use OLE if you need automatic dependency maintenance between Excel and Analytica.

Examples

These expressions are different ways to get the same result, the value from cell C7 in the first sheet, "Sheet1" of workbook: 

SpreadsheetCell( workbook, "Sheet1", "C", 7 )
SpreadsheetCell( workbook, "Sheet1", 3, 7 )
SpreadsheetCell( workbook, 1, 3, 7 )

Suppose the spreadsheet contains a 2-D table in the region C4:J19. The columns of this table correspond to the years 2008..2015. The rows correspond to different assets. It is easier to refer to the columns by number, so that the columns "C" thru "J" are columns 3 thru 10. To hold this 2-D table, we need two indexes in Analytica, Time and Asset. 

 Index Time := 2008..2015
 Index Asset := 1..16
 Variable Workbook := SpreadsheetOpen( "C:\Asset Data.xls" )
 Variable Data := SpreadsheetCell( workbook, "Sheet1", @Time+2, @Asset+3 )

SpreadsheetRange( workbook, range, colIndex, rowIndex, howToIndex, sheet)

Reads a range of cells from an Excel worksheet. The range can be the name of a named range in the Excel workbook, or it can be a cell range such as: "C7" or "C7:F12".

Parameters:

  • «workbook»: A workbook object returned by SpreadsheetOpen
  • range: A cell range. This may be a named range label in the spreadsheet, or it may be of the form "Sheet1!A1:BC99" or "A1:BC99". In the latter case, the «sheet» parameter must also be specified.
  • «colIndex»: (optional) A pre-existing index for indexing the column dimension of the result.
  • «rowIndex»: (optional) A pre-existing index for indexing the row dimension of the result.
  • «howToIndex»: (optional) A set of flags controlling how the result is indexed when colIndex or rowIndex is not specified. Any of the following values can be added together for this parameter:
    • 1 = Force column index. Forces a column index to be included even if the range spans only a single column. Has no effect if colIndex is specified.
    • 2 = Force row index. Forces a row index to be included even if the range spans only a single row. Has no effect if rowIndex is specified.
    • 4 = Use first row for column labels: The first row in the range is not included in the result returned, but the values in the first row are used as the column labels for the local index .Column.
    • 8 = Use first column for row labels: The first column in the range is not included in the result returned, but the values from the first column are used as row labels for the local index .Row.
    • 16 = Do not issue an error if the supplied colIndex or rowIndex are not the correct length.
  • «sheet»: The name of a worksheet inside the workbook, or a number.

Note: Options 4, 8 and 16 require release 4.1.1 or later.

Depending on the dimensions of the cell range, the result may be a scalar (single cell), a column vector, a row vector, or a 2-D array.

If the range spans more than one column in the spreadsheet, then the result must be indexed by a column index. If you already have this index, you can specify it in the optional colIndex parameter; otherwise, a local index named .Column is created by the function to serve as a dimension of the result. By default, the elements of the column index are set to the sheet's column labels, e.g., "A","B",...."AA","AB",..]. If desired, you can also use the first row of values as elements for the .Column index (this row is then not included in the actual array retrieved -- thus should only be used when the range spans at least two rows). To use the first row for the elements of the local column index, specify howToIndex:4 and leave the «colIndex» parameter unspecified.

If your result falls entirely within a single column, but you wish to force a local column index to be included, so that the result is a 2-dimensional array of size 1xR, rather than a 1-D vector of length R, then specify howToIndex:1. If you are using a named range and don't know how many columns there actually are, and it is possible there is only one, then you would want to force a column index so that an error doesn't occur if you use result.Column in an expression.

If the range spans more than one row in the spreadsheet, then a row index must dimension the result. If you already have this index, specify it in the rowIndex parameter; otherwise, if the range spans more than one row, a local index named .Row is created by the function and used to dimension the result. The local .Row index that is created contains the row numbers from the spreadsheet as its elements, so for example, if the range is "C7:F12", the .Row index would contain the elements [7,8,9,10,11,12]. To force the creation of a local .Row index when the result spans only a single row, specify howToIndex:2. To use the values from the first column as the elements of the local .Row index, specify howToIndex:8.

If you specify «colIndex» or «rowIndex», and the length of the indexes do not match the length of the specified range, the range is truncated if the index is too short, or the result filled with Null values beyond the range length if the index is too long. If the flag howToIndex:16 is specified, an error is issued if the index length does not match.

Empty cells in the range are Null in the result.

No dependency is maintained between the original data in the spreadsheet and the result. The data retrieved are the value that were there at the time the function is evaluated. If the data in the spreadsheet changes after the function has been evaluated, the results are not invalidated and continue to retain the original values.

Examples

These example use the following spreadsheet:

WorksheetRange ExcelShot.jpg

In the above spreadsheet, several cell ranges are labelled as named ranges, as follows:

Label Range
Rate B1
Year B3:F3
Cash_flow B4:F4
Divisions A7:A9
Employee_count B7:F9 


SpreadsheetRange( wb, "Rate" ) → 0.08

SpreadsheetRange( wb, "Sheet1!B1") → 0.08

SpreadsheetRange( wb, "Sheet1!B3:F3" ) →
.Column → 'B' 'C' 'D' 'E' 'F'
2008 2009 2010 2011 2012 
Index Year := CopyIndex( SpreadsheetRange( wb, "Year", howToIndex:1 ) );
SpreadsheetRange( wb, "Cash_flow", colIndex:Year ) 
→
.Year → 2008 2009 2010 2011 2012
-100 10 30 50 60

Note: howToIndex:1 was specified for Year here so that we would have a 1-D array even if only one year were present in the spreadsheet. 

SpreadsheetRange( wb, "Employee_count" ) →
.Column → 'B' 'C' 'D' 'E' 'F'
.Row
↓		 7 24 27 28 32 35
8 13 13 13 13 13
9 25 22 21 19 16 
Index Time := [2008,2009,2010,2011,2012];
SpreadsheetRange( wb, "A7:F9", colIndex:Time, howToIndex:8, sheet:1)
→
Time → 2008 2009 2010 2011 2012
.Row
↓		 "Div A" 24 27 28 32 35
"Div B" 13 13 13 13 13
"Div C" 25 22 21 19 16

Legacy Notes

Functions for reading cells from Excel were first present in Analytica 4.1 with functions named OpenExcelFile, WorksheetCell and WorksheetRange, although these were labelled as experimental, and the present functions were not officially available until 4.2.0. The old names are now deprecated, replaced with SpreadsheetOpen, SpreadsheetCell and SpreadsheetRange. The old functions still work at present, but may be removed in future Analytica builds. The parameters have changed slightly from WorksheetRange to SpreadsheetRange, with the sheet parameter moved from being the second to being the last parameter and now optional -- no longer required for named ranges or ranges of the form "Sheet1!A1:Z99".

See Also

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