Can't compare two strings

[uriel]

Hello, I can't check if this string "operation = str(lst[1])" is equal to a mathematical symbol and that the check is carried out indefinitely:

def solution():
    print("Enter an equation")
    calc = input()
    lst = calc.split(' ')
    global x
    global y
    global operation
    while True:
        try:
            operation = str(lst[1])
            x = float(lst[0])
            y = float(lst[2])
        except ValueError:
            print("Do you even know what numbers are? Stay focused!")
            print("Enter an equation")
            calc = input()
        if operation == '+' or operation == '-' or operation == '*' or operation == '/':
            print(calc)
            break
        else:
            print("Yes ... an interesting math operation.You've slept through all classes, haven't you?")
            print("Enter an equation")
            calc = input()


solution()

[bowlofred]

lst comes from input(), so it is already a "str". The splits you do keep it. So lst[1] will always be an str, you don't need to cast it further.

operation = lst[1]

You could just see if it's in a collection of mathematical symbols that you want.

if operation in "+-*/":
    ...

Your "else" section will report that the input doesn't have your correct operation. But it doesn't do the right thing. It asks for input and puts that data in calc. But when the loop is rerun, calc is never referenced. The code only looks at lst

The split code to parse the input into portions has to be inside the loop somewhere, otherwise it is only performed once.

[uriel]

Thank you, man! I find a solution)