n.n.h. (noob needs help) Ok, I've been beating my head against this for a day... time to ask others. To explain things as simply as possible: I am trying to use eval() to evaluate some simple equations, such as-- pow(AB,2) pow(AB,2)+A pow(A+B,2) pow(A+B,2)+A and so forth... for a variety of math operations (+,-,*) and a variety of variables, all of which have been genrated by a script, written to a .txt file., then recalled sequentially and passed to eval().
The variables (A,B,C,D) are generated elsewhere [Note: AB is a concat, e.g. A=2,B=7,AB=27] , so both are passed into a function e.g. def (equation, list): A=list[0] B=list[1] ...etc. return eval(str(equation)) Where 'equation' is one of the above, selected from the "equations file" So here's the rub: With the above examples everything works fine... up to the last (pow(A+B,2)+A), then it bombs with: ValueError: invalid literal for int(): - And I have tried 'hard typing' the vars e.g. A=str(list[0]) and A=int(str(list[0]))... which only leads to it breaking in the other expressions. I have also tried 'compile()', which bombs the same way, and have also looked at 'pickle' (but I don't think I really need to go that far)... All of which leaves me wondering... Could it simply be that eval() can't handle the progressive order of math operations? Because pow(AB,2) + A works, as does pow(A+B,2)... but then adding pow(A+B,2)+A (the result, *plus* A) doesn't? Or is the problem deeper (like at the dictionary level)? Either way I'm stumped, and could use some help. Thanks Robb Drinkwater -- http://mail.python.org/mailman/listinfo/python-list
