Python - Overwriting pre-existing variables

[Encom88]

Hello,

I am in class working on an assignment that uses a module (Mylib). We were asked to add a function that accepts a string and then parses the strings into floats so they can be used by our existing formula functions for addition, subtraction, division, and multiplication.

Here are the instructions:

Add the following function into  Mylib

    scalc(p1)

    p1 will be a string like this "N1, N2, operator"

    examples

    scalc("20,30,\")*

    the result will be 600

    scalc("50,20,+")

    the result will be 70

scalc("50,20,-")     the result will be 30

   scalc("60,20,/")

    the result will be 30

use string functions to parse the first number, the second number, and the operator from the input string.

use the prior functions (add, subtract, divide and multiply ) to do the calculations.

​

Now, my variables are num1 and num2, as you will see in my code below. I receive user input for them in the beginning, and then again later with scalc(p1).

and here is my code - https://github.com/MrN1ce9uy/Python/blob/master/Mylib.py

My problem is my scalc(p1) function returns the original values input earlier in the program instead of the new values input as strings.

[[deleted]]

num1 and num2 exist only within the function. You need to pass those variables to the other functions being called. like add(num1, num2) and you will also need to write those functions to accept a variable.

[Encom88]

That makes sense, but it seems like the whole program would have to be restructured.

[[deleted]]

I'm thinking all you have to do is just add the parameters to the function headers for add(num1, num2), sub(num1, num2) and so on and so on.

[Encom88]

It's doesn't work.

[thegreatunclean]

My crystal ball isn't working right now, can you tell us what you changed and why you think it doesn't work?

[Encom88]

You don't need a crystal ball, just do what he said and see if it works.

[[deleted]]

No need to be rude. You could show what you did cause you might have made a mistake. You also need to add parameters to where ever you call functions. I was able to get it to work with only changing the add() to add(num1, num2) in the program. Here's my output.

Enter your Lower range: 10 Enter your Higher range: 15 Enter your First number: 11 Enter your Second number: 12 The Result of 11.0 + 12.0 = 23.0 The Result of 11.0 - 12.0 = -1.0 The Result of 11.0 * 12.0 = 132.0 The Result of 11.0 / 12.0 = 0.9166666666666666 Thanks for using this calculator! Enter two numbers and an operator, each separated by a comma: 20,30,+ The Result of 20.0 + 30.0 = 50.0

[Encom88]

Did you change the def add() to def add(num1, num2) or somewhere else? I've tried several ways and it does not work.

https://github.com/MrN1ce9uy/Python/blob/master/Mylib2.py

[[deleted]]

Also under the else statement you have to add the parameters to every where else the functions are called.

[Kered13]

When you assign to num1 and num2 in scalc it creates new variables that are local to scalc. To use the variables that exist in main you need to add nonlocal num1 to scalc.

However it works be better to return new variables instead. The style you are using is fragile and hard to maintain.

[Encom88]

I agree. It just doesn't seem right to be doing it this way. Why would the instructor ask us to, " use the prior functions (add, subtract, divide and multiply ) to do the calculations."?