19-May-2026 Self-Practice 6

def check_num(op):
    try:
        num = float(op)
        return True, num
    #except ValueError as d:
    
        #print("Cannot convert into value !")
        #print (d)
        #return False,
    except Exception as e:
        
        #print('Invalid Input')
        print (e)
        return False,
        
def check_op(operator):
    if operator in ('+', '-', '*', '/'):
        return True, operator
    else:
        return False,

def calc(x, y, z):
    if x[0] and y[0] and z[0]:
        if z[1] == '+':
            result = x[1] + y[1]
            return result
        if z[1] == '-':
            result = x[1] - y[1]
            return result
        if z[1] == '*':
            result = x[1] * y[1]
            return result
        if z[1] == '/':
            if y[1] == 0:
                return False
            else:
                 result = x[1] / y[1]
                 return result
    else:
        print("wrong expression")
        return False

#print(calc(check_num(a), check_num(b), check_op(c)))    
    
exp = '4 + 2 * 3'

ls = exp.split()

while len(ls) >= 3 and len(ls) % 2:
    x = ls[0]
    y = ls[2]
    op = ls[1]
    result = calc(check_num(x), check_num(y), check_op(op))
    if result != False:
       del ls[:2]
       ls[0] = result
    else:
       break
   
print(ls)