Python，完了？

Question

好的，我终于开始在Python中学习数学了，结果发现其实并没有我想象中的那么难（我不懂微积分或三角函数，只会一些基础的代数）。

我正在尝试从零开始写一个程序，用来分解二次方程。到目前为止，我写的代码是这样的（如果写得不好请见谅）：

def factor(arg):    
    o = arg
    n = o
    x = 2
    factors = [o]

    while abs(o) >= x:
        if (o) % x == 0:
            n = o / x
            factors.append(n)
            x += 1
        else:
            x += 1

    return factors

A = int(raw_input("What is A in your quadratic equation?   A = "))
B = int(raw_input("What is B in your quadratic equation?   B = "))
C = int(raw_input("What is C in your quadratic equation?   C = "))

Br = abs(B) + abs(A)            # Range of B
Bpf = range (-Br, Br + 1)       # Possible factors of B
ACpf = factor(A * C)            # Possible factors of (A * C)

for i in ABpf:
    ACpf.append(-i) 

cf = []                          # Common factors

for i in Bpf:
    for j in ACpf:
        if i == j:
            cf.append(i)

print cf

我在终端运行了这个脚本，它让我输入A、B和C的值，然后大约卡了三十秒。等它恢复后，下面显示了我输入的内容，并且说“被杀掉了”。

有没有人知道这是为什么呢？我很感激任何的回答或建议。

Answer 1

看起来问题出在这些代码行：

ACpf = factor(A * C)            # Possible factors of (A * C)

for i in ABpf:
    ACpf.append(-i) 

试试这个：

ACpf = factor(A * C)            # Possible factors of (A * C)

for i in ACpf[:]:               # Loop over a copy of ACpf
    ACpf.append(-i) 

这个 [:] 的写法是用来复制列表的。这样可以确保你在遍历列表的时候，不会改变它的内容（比如增加元素）。

另外，这里对 factor() 函数的代码做了一些简化：

def factor(arg):
    o = arg
    factors = [o]

    for x in range(2, o+1):
        if o % x == 0:
            n = o // x
            factors.append(n)

    return factors

Answer 2

把你的代码稍微改成这样：

def factor(arg):    
    o = arg
    n = o
    x = 2
    factors = [o]

    while abs(o) >= x:
    if (o) % x == 0:
        n = o / x
        factors.append(n)
        x += 1
    else:
        x += 1

    return factors

A = int(raw_input("What is A in your quadratic equation?   A = "))
B = int(raw_input("What is B in your quadratic equation?   B = "))
C = int(raw_input("What is C in your quadratic equation?   C = "))

Br = abs(B) + abs(A)            # Range of B
Bpf = range (-Br, Br + 1)       # Possible factors of B
ABpf = factor(A * C)            # Possible factors of (A * C)
ACpf = []
for i in ABpf:
    ACpf.append(i)
    ACpf.append(-1*i) 

cf = []                          # Common factors

for i in Bpf:
    for j in ACpf:
    if i == j:
        cf.append(i)

print cf

现在试着运行一下。你应该能看到结果。