当 elif 行为真时，中断功能不起作用

Question

start = input('Enter quadratic equation: ')
w = start.split()
while len(w) != 7:
    start = input('Enter quadratic equation correctly: ')
    w = start.split()
while x < len(w):
        if "x" in w[x] and '^2' in w[x]:
            a = w[x]
            if a == "x^2":
                a = 1
            else:
                a = a.replace('x^2', '')
                a = int(a)
            if w[x-1] == '-':
                a = a * (-1)
            else:
                a = a
        elif 'x' in w[x] and '^' not in w[x]:
            b = w[x]
            if b == 'x':
                b = 1
            else:
                b = b.replace('x', '')
                b = int(b)
            if w[x-1] == '-':
                b = b * (-1)
            else:
                b = b
        elif w[x].isdigit() and 'x' not in w[x] and w[x] != '0':
            c = w[x]
        elif w[x] == '-' or '+' or '=':
            s = 0
        elif not w[x].isdigit() and 'x' not in w[x] and w[x] != '-' or '+' or '=':
            print('Mistake')
            break #Would not this code here work?
        x += 1

我试过只做 'else' 块，但仍然行不通。我想做的是检查输入是否实际上是二次方程。

Answer 1

错误的条件是 elif not w[x].isdigit() and 'x' not in w[x] and w[x] != '-' or '+' or '=':，它不符合您的要求 want/need

w[x] != '-' or '+' or '=':部分：

就像(w[x]!='-') or ('+') or ('='):
不喜欢w[x] != ('-' or '+' or '='):

你要的是w[x] not in '-+=':和上一个一样

    elif w[x] in '-+=':
        s = 0
    elif not w[x].isdigit() and 'x' not in w[x] and w[x] not in '-+=':
        print('Mistake')
        break

当 elif 行为真时，中断功能不起作用

Break function does not work when the elif line is true

python

if-statement

while-loop

break