Variable Names

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The scripting language can define variables in command files and do calculations on variables using expressions.

Defining Variables

Variables are defined and used in the form #varname where varname is any valid variable name. A number sign must always be used to indicate a variable (although the number sign is optional in NairnFEAMPMViz, it is recommended to use it for compatibility). The rules for a valid variable name after the number sign (or entire name if number sign omitted in NairnFEAMPMViz) are:

  • It must start with a letter (a-z or A-Z) or an underscore (_).
  • It can be followed by any number of additional upper (A-Z) or lower (a-z) case letters, underscores (_), or numbers (0-9).
  • Variable names are case sensitive.
  • In NairnFEAMPMViz, string variables must end in a dollar sign ($) while numeric variables must not. In NairnFEAMPM, a variable can optionally end in a dollar sign ($) and for compatibility, it is good practice to end string variables with a dollar sign.
  • In NairnFEAMPMViz, the name cannot contain any supported function name as a substring within the name.

Initializing a Variable

A variable is initially defined in an assignment statement such as:


where the variable is set equal to the right side of the equals sign which can be any valid expression. A variable cannot be used in an expression until it has been defined.

Variable Arrays

Any valid variable name can be a variable array by following it with an expression in square brackets



  • The expression in the square brackets must evaluate to an integer index into the array.
  • Multidimensional arrays are allowed such as #z[#i][#j].
  • There is no need to define the dimension of arrays.