AttributeError：类型对象'BST'没有属性'contains'

如何解决AttributeError：类型对象'BST'没有属性'contains'

我不断收到属性错误，即BST包含属性时不包含该属性，这是一个简单的BST程序，用于检查节点是否包含子树。

我是python的新手，所以我不知道这里的问题是什么，我们将不胜感激。

from collections import namedtuple


class BST:
    #We are using namedtuple since it allows us to create an object with names for each position
      tuple = namedtuple('tuple',['left','right','value'])



#here,contains is a static method since we have to create a utility function to check 
#if the node has the value in its subtrees.

@staticmethod
def contains(root,value):
      if root.value == value:
          return True
        
     #means the value is greater than the root node and must lie on the right sub-tree.
      elif root.value < value:
            
            #if the right subtree is empty,than the said node does not contain the value,return false.
          if root.right == None:
               return False
            
            
            
           #it does contain a right subtree,recursively call the contains method again till you find the value.
          else:
               return BST.contains(root.right,value)
            
     #else,root value is lesser than the root node and must lie on the left side.
      else:
            
        
        
        #if the left subtree is empty,return false.
          if root.left == None:
              return False
          else:
              return BST.contains(root.left,value)
         


n1 = BST.tuple(value=1,left=None,right=None)
n3 = BST.tuple(value=3,right=None)
n2 = BST.tuple(value=2,left=n1,right=n3)



result= BST.contains(n2,3)
print (result)

解决方法

您的静态方法被错误地缩进。在Python中，由于没有括号来表示类的结尾，因此任何与在类定义后与Python代码的第一部分处于同一级别的缩进都被视为该类的一部分。

像这样缩进您的静态方法，它将起作用：

class BST:
    #We are using namedtuple since it allows us to create an object with names for each position
    tuple = namedtuple('tuple',['left','right','value'])



    #here,contains is a static method since we have to create a utility function to check 
    #if the node has the value in its subtrees.
    @staticmethod
    def contains(root,value):
        ....

P.S。我建议不要将tuple用作类的属性名称，因为它是built-in function，并且应该始终可用（不要被名称空间中的其他内容所遮盖）。