Question

为标题道歉，我不知道我要做的事情的术语。

我有一个具有一系列嵌套循环的函数，它运行了很多次。循环有许多条件，无论它们是继续还是重新开始。

有时会调用此函数，使其需要满足某些稀有的条件。但是，要检查它们，我需要在我的代码中添加更多if语句。

以下是我所谈论的一个例子，我函数中的一些循环：

while 1:

    for node in currset:

        for (sum1, weight1, l1, r1) in pathdict[(0, node)]:  
            if sum1 & sum != sum1 or r1 == left or r1 == right or l1 == left:
                continue

            if level < connectright:
                if l1 == right:
                    continue
            elif l1 != right:
                    continue

            for (sum2, weight2, l2, r2) in pathdict[(level, r1)]:
                if sum2&sum != sum2:
                    continue
                if l2 != left or l2 == right:
                    continue
                andsum = sum1&sum2

                if andsum != r1:
                    continue

现在，如果我有一个特殊情况，其中许多条件不再适用，我该怎么办？我现在看到它的方式，我可以1.）编写一个全新的函数，2。）重写整个代码块并将其放在另一个if语句之后，3。）添加一系列更多条件，或者4。）编写一个在给定步骤检查我的条件的函数。

前两个选项看起来很笨重，但至少我的代码会很快。第三个似乎很糟糕，因为代码变得难以阅读，而且速度变慢。第四，我不确定，但似乎多次调用这些函数会减慢我的循环。

所以我的问题是，是否有某种方法可以编写“条件if语句”，根据传递给函数的变量，我可以做类似的事情：

if variable_passed == thing#1:
     my_if_statement = (if level < connectright:  continue)
else:
     my_if_statement = (if level > connectright:  continue)

这样，在开始循环之前，我可以在函数开始时轻松更改条件。

Answer 1

您可以创建所有采用相同参数的函数列表，并使用参数的子集计算条件。

除非你有很多，或者正在产生条件，否则对我来说看起来有点太多了。

一个例子：

outer = [  # lambda parameters are all that could be used in any expression at point of call
            (lambda sum, sum1, weight1, l1, r1, left, right, level, connectright:
                sum1 & sum != sum1 or r1 == left or r1 == right or l1 == left),
            (lambda sum, sum1, weight1, l1, r1, left, right, level, connectright:
                level < connectright),
            (lambda sum, sum1, weight1, l1, r1, left, right, level, connectright: 
                l1 != right),
        # ... add extra outer loop conditions as necessary
        ]
inner1 = [  # lambda parameters are all that could be used in any expression at point of call
            (lambda sum2, weight2, l2, r2, sum, sum1, weight1, l1, r1, left, right, level, connectright: 
                sum2&sum != sum2),
            (lambda sum2, weight2, l2, r2, sum, sum1, weight1, l1, r1, left, right, level, connectright: 
                l2 != left or l2 == right),
        # ... add extra inner loop conditions as necessary
        ]
inner2 = [  # lambda parameters are all that could be used in any expression at point of call
            (lambda andsum, sum2, weight2, l2, r2, sum, sum1, weight1, l1, r1, left, right, level, connectright: 
                andsum != r1),
        # ... add extra inner loop #2 conditions as necessary
        ]

while True:
    for node in currset:
        for (sum1, weight1, l1, r1) in pathdict[(0, node)]:  
            if any(f(sum, sum1, weight1, l1, r1, left, right, level, connectright)
                    for f in outer):
                continue
            for (sum2, weight2, l2, r2) in pathdict[(level, r1)]:
                if any(f(sum2, weight2, l2, r2, sum, sum1, weight1, l1, r1, left, right, level, connectright)
                        for f in inner1):
                    continue
                andsum = sum1&sum2
                if any(f(andsum, sum2, weight2, l2, r2, sum, sum1, weight1, l1, r1, left, right, level, connectright)
                        for f in inner2):
                    continue

if语句可以是变量吗？

1 个答案: