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analysis/
mg_evalexpr.pro
includes main-level programEvaluates a mathematical expression using the basic arithmetic operators +, -, *, /, and ^ along with parentheses for grouping and simple function calls of a single variable.
This routine does not use EXECUTE, so it is safe to use in the Virtual
Machine.
Examples
For example, simple arithmetic expressions can be evaluated:
IDL> print, mg_evalexpr('1 + 2 + 3', error=error), error
6 0
ERROR keyword returns whether there was an error in
evaluating the expression. Expressions can also take variables, if their
values are provided via a structure or hash-like object:
IDL> print, mg_evalexpr('exp(i * pi)', { pi: !dpi, i: complex(0, 1) })
( -1.0000000, 1.2246468e-16)
Author information
- Author
Michael D. Galloy, 2012
Other file information
- Bugs:
does not support functions of multiple variables
top source mg_evalexpr
result = mg_evalexpr(expr [, vars] [, /error])
Evaluates a mathematical expression.
Return value
double or long64
Parameters
- expr in required type=string
expression to evaluate
- vars in optional type=structure or hash
variables to substitute into expression specified as a structure or hash-like object; if a structure, the variable names are case-insensitive
Keywords
- error out optional type=boolean
set to named variable to return if there was an error evaluating the expression
File attributes
| Modification date: | Mon Jan 30 14:30:40 2012 |
| Lines: | 379 |
| Docformat: | rst rst |
Contact me if you have enhancement requests or bug fixes.