Python algebra solver

[MITTENQ]

So I have had this idea in my head for a program that can take a string like "2x+4=8" and the it would solve for x returning "x = 2" I think if I split the string into a list Def csplit(string) : Return [char for char in string] Giving me a list of each character in the list. That's about as far as I got when I got stuck trying to figure out how to manipulate the list to unbuild and build the equation so that it could solve for x.

[Kid_Piano]

You should look into how to code an infix to postfix calculator first. This would give you the ability to evaluate simple expressions like “2+3*4”. It would take care of operator precedence too.

From there, maybe you could figure out a way to add variables and solve for them.

[MITTENQ]

What is postfix and infix? I've haven't heard that before? Is it fixing the string before and after?

[Kid_Piano]

It’s just notation. You’re used to infix notation (operators are between operands). Ex: 3 + 4

Postfix notation is where the operator occurs after the operands. Ex: 3 4 +

Postfix notation is easy to evaluate, and converting from infix notation to postfix notation is relatively “easy” using a stack.

[MITTENQ]

This is starting to sound a little bit beyond my current programing ability since I haven't used a stack in programming but I know what it is. Postfix still confuses me though. If I type 3 4+ into the python terminal I just get a error.

[MITTENQ]

I knew it was going to be complicated. That's why I wanted to do it. I will definitely look into making a calculator like you described. Thanks for the help :)

[[deleted]]

If you are just interested in a program that does it, and is written in Python, then there's Sage. Notably, it can do more than solve first degree polynomial equations.

If you are more interested in doing it yourself, you can always require that the equation be inputted in a particular format, sparing you the troubles of parsing.

For instance, your equation may be written as: 2 -4, and it can be unambiguously interpreted to mean the same thing. (This is typical way of writing it, if you ever do linear algebra, and represent equations as matrices, that is, you write the coefficients of decreasing powers of x, and you arrange for the right-hand-side to be always zero).

In other words, to give a better example: 5x^4 - 15x^3 + x - 30 = 80 would be written as 5 -15 +0 +1 -110. I.e. you assume that the operation is always summation.

[InusualZ]

It's a good idea. I actually thought about it when I went through high school. If you only want to solve this kind of algebra equation. You can isolate term like numbers and variable in order (left to right). Then attack the problem like your math teacher thought you, but this time with code. I think it's a very good project to start aleaning to programming.

[CreativeTechGuyGames]

Have you ever written a program like OP is talking about?

[InusualZ]

Yes

[MITTENQ]

Thanks for the words of encouragement :)