python - 为什么我收到 TypeError : cannot unpack non-iterable builtin_function_or_method object?

Question

我是编码新手，我从 python 开始。我正在尝试制作一种方法，该方法将采用方程并求解未知变量。
它只适用于一个方程(一个运算符)，但当我试图让它基于运算符返回值时不起作用。

这有效:

def solveforx(y):
    x, add, num1, equal, num2 = y.split()

    # convert the strings into ints
    num1, num2 = int(num1), int(num2)
    # convert the result into a string and join it to the string "x = "
    return "x = "+ str(num2 - num1)

print(solveforx("X + 5 = 9"))

这没有:

def solveforx(y):
    x, op, num1, equal, num2 = y.split

    num1, num2 = int(num1), int(num2)

    if op == "+":
        return "x = " + str(num2 - num1)
    elif op == "-":
        return "x = " + str(num1 + num2)
    elif op == "*":
        return "x = " + str(num2/num1)
    elif op == "/":
        return "x = " + str(num1*num2)
    else:
        return "wrong operator"

print(solveforx("X + 5 = 9"))

TypeError: cannot unpack non-iterable builtin_function_or_method object

Answer 1

你忘记了 y.split 后面的括号，所以你试图解压方法 split而不是它的实际结果。

它应该是

x, op, num1, equal, num2 = y.split()