How to define function in class properly in Python? -


this question has answer here:

i want define function sumofleftleaves recursively:

class node(object):   def __init__(self,x):   self.val = x   self.left = none   self.right = none  class solution(object):   def sumofleftleaves(self,root):     if root.val == none:       return 0     elif (root.left.left == none , root.left.right == none):       return root.left.val + sumofleftleaves(root.right)     else:       return sumofleftleaves(root.left)+sumofleftleaves(root.right)

but gives error "nameerror: global name 'sumofleftleaves' not defined", think it's defined recursively, what's wrong?

sumofleftleaves still method on class , not globally defined function. can access bound method on self, you'd access other method:

self.sumofleftleaves(...)

you should use is none when testing none object well:

class solution(object):     def sumofleftleaves(self, root):         if root.val none:             return 0         elif (root.left.left none , root.left.right none):             return root.left.val + self.sumofleftleaves(root.right)         else:             return (self.sumofleftleaves(root.left) +                      self.sumofleftleaves(root.right))

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