[我编写了一个简单的程序，使用python返回树中节点的级别，但未返回任何内容

Question

class Node:
def __init__(self,data):
    self.data=data
    self.left=self.right=None
def insert(self,data):
    if self.data:
        if data<self.data:
            if self.left is None:
                self.left=Node(data)
            else:
                self.left.insert(data)
        elif data>self.data:
            if self.right is None:
                self.right=Node(data)
            else:
                self.right.insert(data)
def level(self,data,l):
    if data<self.data:
        if self.left is None:
            return -1
        self.left.level(data,l+1)
    elif data>self.data:
        if self.right is None:
            return -1
        self.right.level(data,l+1)
    elif self.data==data:
        print(l)    

l = [8,7,6,5,10]根=节点（l.pop（0））对于我在l中：root.insert（i）预（根）l = root.level（10,1）打印（l）预期输出为2但返回None

Answer 1

class Node:
  def __init__(self,data):
      self.data=data
      self.left=self.right=None

  def insert(self,data):
    if self.data:
      if data<self.data:
        if self.left is None:
            self.left=Node(data)
        else:
            self.left.insert(data)
      elif data>self.data:
        if self.right is None:
            self.right=Node(data)
        else:
            self.right.insert(data)

  def level(self,data,l):

    if data == self.data:
      level = l
    else:
      if data<self.data:
        if self.left is None:
            return -1
        level = self.left.level(data,l+1)
      elif data>self.data:
        if self.right is None:
            return -1
        level = self.right.level(data,l+1)

    return level

l=[8,7,6,5,10] 
root=Node(l.pop(0)) 
for i in l: 
  root.insert(i) 

print(root.level(8,1))
print(root.level(7,1))
print(root.level(6,1))
print(root.level(5,1))
print(root.level(10,1))

您的函数应该返回一些东西，还需要更新级别。