Answer by Eviatar Bach for Context: I want to evaluate a symbolic expression numerically; however sometimes this expression still depends on some symbolic parameters not yet assigned a value.Question: What is the best way to avoid "TypeError: cannot evaluate symbolic expression numerically" in such a situation?In other words, is there a function (or an equivalent construction) for if isThisSymbolicExpressionNumericallyEvaluabel(exp): n = exp.n() else: print "sorry, no"

You should be able to just check if it has no variables. def is_numerically_evaluable(expr): return not expr.variables() Then: sage: is_numerically_evaluable(sin(1)) True sage: is_numerically_evaluable(x) False