Variable names can be of any length and contain any characters. Variable names containing special characters must be surrounded by double quotes "" when used in equations. If you use the Sketch and Equation editors, Vensim will automatically add the quotes.
Variable names do not need to be surrounded by quotes if they start with a letter, or international character, and contain only letters, international characters, numbers, single quotes ' and dollar signs $.
Variable names can contain spaces and underbars _ and the two are considered interchangeable. If two or more spaces or underbars appear side by side, they will be collapsed to a single space (for example Hello _ _ __ There will become Hello There). When you work with Vensim you can choose whether to have variable names appear with a space or underbar _.
Variable names cannot contain an explicit line break. In the Equation Editor, this means that you cannot add a Ctrl+Enter sequence within a variable name. Line wraps, entered automatically by the Equation Editor, do not present a problem. In the Text Editor, lines ending with a backslash \ will be assumed to be continued. Vensim will add line continuation characters automatically when you move between the Text and Equation Editors.
Variable names are not case sensitive, but Vensim is case retentive==F_11}. Vensim will use the capitalization that first appears for a variable name. If you use the Text editor to enter a model, it is the first occurrence (not the defining equation) of a variable that defines the case that will be retained. With the Sketch editor it is the way you first enter it. You can change the capitalization of a variable name by retyping it in the Sketch Editor or by replacing all occurrences of the variable in the Text Editor.
With the exception of String Variables, all variables in Vensim are treated as single-precision floating point numbers. Vensim DSS is optionally available in configuration that uses double precision computation (but single precision storage).
Examples
TOTAL_COST
total cost
Total _ Cost
The above would all be recognized as the same variable
"Color TV Sets & VCRS"
Color TV Sets[SONY]
"R & D"["Gov & Foreign"]
Using quotes in subscripts can be confusing and is not recommended.
"HiRes TV/Web Sets"[ASIA,country,SONY]
"The \"Final\" Frontier"
Quotes embedded within variable names must be preceded by a backslash \
érosion d'action
Uses international characters but does not require quotes.
