Python无法分配运算符错误

Question

I am new to python and started coding a little less than a week ago. I decided that I want to try and build a single diget calculator. I know my code may not be very well written and suggestions appreciated but please dont just hate on it. Well now to the code. I am getting the error on the code saying that it cant assign an opperator. I know that it means it can not make the variable into from string to int. But I am not sure how to fix it. Also I get the error on line 25, 28, 31, 34. Thanks!

calculate = input("Enter the problem in the format x + y = z ")

opperations = ["+", "-", "*", "/"]
numbers = ["0", "1", "2", "3", "4", "5", "6", "7", "8", "9"]
space = " "

def opperation():
    if opperations == "+":
        A = 1
    elif opperations == "-":
        A = 2
    elif opperations == "*":
        A = 3
    elif opperations == "/":
        A = 4

if calculate[0] in numbers:
    if len(calculate) > 1:
        if calculate[1] == space:
            calculate[0] = a
            a = int(a)
            calculate[4] = b
            b = int(b)
            if A == 1:
                a + b = c
                print (c)
            elif A == 2:
                a - b = c
                print (c)
            elif A == 3:
                a * b = c
                print(c)
            elif A == 4:
                a / b = c
                print(c)
            else:
                print("Sorry invalid text")

        else:
            print("Sorry invalid text")
    else:
        print("Sorry invalid text")
else:
    print("Sorry invalid text")

Answer 1

You cannot have an operation in the left-hand side of an assignment. You should do the operation in the right-hand side :

c = a + b
c = a - b

Also, you are using b in the line

calculate[4] = b
b = int(b)

before declaring it. You have to declare it first. So, you may want to check your logic there.

Answer 2

Your problem is that you use = operator in wrong way. How it works is that it evaluates what is on the right , and assigns it to what is on the left . So instead a + b = c , it should be:

c = a + b

What you have tried to do, was to assign value of c to the expression a + b , which does not make any sense.

Answer 3

Your issues are these lines:

a + b = c
a - b = c
a * b = c
a / b = c

Python doesn't work that way. You're trying to do (a + b) = c , which is the same as trying to do, say, 5 = c .

If you want c to be the result of the operation on a and b , you need to flip those lines around, ie c = a + b .