Bharat - 5 months ago 23

Python Question

I have a chat bot for an Instant messenger and I am trying to make a math solver for it but it can't send the solution of equation to the Instant messenger, it sends equation instead.

If someone from Instant messenger sends "solve: 2+2", this program should send them "4" not "2+2".

**Main problem:**

`if (parser.getPayload().lower()[:6]=="solve:"):`

parser.sendGroupMessage(parser.getTargetID(), str(parser.getPayload()[7:]))

it's sending same input again not the answer of equation

I tested something and that's working properly. If I add this code, program will send solution of equation:

`if (parser.getPayload().lower()=="test"):`

parser.sendGroupMessage(parser.getTargetID(), str(2 + 2 -3 + 8 * 7))

Working perfectly

Answer

What you need to do this evaluating math expressions in string form.

However, user inputs are dangerous if you are just `eval`

things whatever they give you. Security of Python's eval() on untrusted strings?

You can use `ast.literal_eval`

to lower the risk.

Or you can use a evaluator from answers of following question Evaluating a mathematical expression in a string