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6.2.6 Constraint Expressions

     

Constraints are limitations or conditions placed on the variables in your spreadsheet. They are expressed as algebraic statements appended to formulas. You can attach a constraint expression to any formula, by typing a semicolon (;) and the constraint conditions after the formula.

Constraint expressions establish conditions under which a formula operates or boundaries for valid results of the formula. Constraint expressions may be simple equality/inequality relationships, or they can be arbitrary formulas. Any valid NExS expression which returns a numeric value is also a valid constraint expression. However, unlike the expression that defines a cell value, a constraint expression can reference the cell in which it resides, using the symbol #.

For example, the formula

=A1 + A2 ; #>2 && #<=B5 || #==C7
means, ``the value of the current cell is the sum of cells A1 and A2, and that value must be either greater than 2 and less than or equal to the value of cell B5, or equal to the value of cell C7.''

Constraint expressions are used in several other contexts within NExS, including the Find and Extract Tools, and the conditional statistical functions.

The benefit of constraint expressions is maximized when combine with current cell reference support (#) as indicated in the above example.


next up previous contents index
Next: 6.2.7 Explicit Dependency Up: 6.2 NExS Formulas Previous: 6.2.5 Cell Referencing in

NExS User's Guide, Version 1.4.5
Grey Trout Software
11 April 1999