How can I correct the error ' AttributeError: 'dict_keys' object has no attribute 'remove' '?

Question

I was trying shortest path finder using dijkstra algorithm but It seems not working. Can\'t figure out what the problem is. Here are the code and the error message. (I\'m w

Answer 1

In Python 3, dict.keys() returns a dict_keys object (a view of the dictionary) which does not have remove method; unlike Python 2, where dict.keys() returns a list object.

>>> graph = {'a': []}
>>> keys = graph.keys()
>>> keys
dict_keys(['a'])
>>> keys.remove('a')
Traceback (most recent call last):
  File "", line 1, in 
AttributeError: 'dict_keys' object has no attribute 'remove'

You can use list(..) to get a keys list:

>>> keys = list(graph)
>>> keys
['a']
>>> keys.remove('a')
>>> keys
[]

---

unseen_nodes = graph.keys()

to

unseen_nodes = list(graph)