Question

I have this method:

def is_active(self):
    if self.is_current_node():
        return True
    cur_children = self.get_children()
    while cur_children is not None:
        for child in cur_children:
            if child.is_current_node():
                return True
            raise Exception(child.display_name)
        cur_children = cur_children.get_children()
    return False

I put this method together and I put the raise Exception(child.display_name) to test out and “alert()” me to which child was being hit. The exception is never raised. You’d think that was because the function returned True on the if child.is_current_node() part. Well, if I replace the if part with this:

        for child in cur_children:
            if child.is_current_node():
                raise Exception(child.display_name)

It doesn’t raise the exception still. If I do this however:

        for child in cur_children:
            raise Exception(child.display_name)

The exception is raised. I’m so confused. I’m sure this is something ridiculous but I was up till 2 and I can’t think straight enough to wrap my tiny brain around this.

Answer 1

Some ideas:

cur_children = self._children
while cur_children is not None:
for child in cur_children:
if child.is_current_node():
return True
raise Exception(child.display_name)
cur_children = cur_children._children

I assume that self._children contains multiple children: [A, B, C]

Then, on the first loop, it will take A. Let’s assume that A has these children: [AA, AB, AC].

Now, you do this: cur_children = cur_children._children. This means that now, instead of continuing with B from the inital [A, B, C], it will continue with AA, and so on.

In this example, it will never reach B. Is this intended?

---

What does your is_current_node() contains? Probably you forgot to return a value, so the result is always None, and bool(None) == False.

---

Another idea: (recursion)

def is_active(self):

    def check_children(children):
        for child in children:
            if child.is_current_node():
                return True
            else:
                if children._children:
                    return check_children(children._children)
        return False

    if self.is_current_node():
        return True
    return check_children(children)