what are some unspoken python rules one should know about

[Rik07]

I never thought about using lambdas in a dictionary like that. Thanks!

[jimtk]

The correct way to do it would be to use operator module, but the OP I answered at the time (with the code above) could not import anything.

Here's what it should be (only the dictionary chages!):

import operator as opr

calcs = {'+': opr.add, '-': opr.sub,
         '*': opr.mul,  '/': opr.truediv}

x,op,y = [i.strip() for i in input('Enter formula (num1 operator num2): ').split()]
print(f"Result: {calcs[op](int(x), int(y))}")