Somehow, in the Node class below, the wordList
and adjacencyList
variable is shared between all instances of Node.
>>> class Node:
... def __init__(self, wordList = [], adjacencyList = []):
... self.wordList = wordList
... self.adjacencyList = adjacencyList
...
>>> a = Node()
>>> b = Node()
>>> a.wordList.append("hahaha")
>>> b.wordList
['hahaha']
>>> b.adjacencyList.append("hoho")
>>> a.adjacencyList
['hoho']
Is there any way I can keep using the default value (empty list in this case) for the constructor parameters but to get both a
and b
to have their own wordList
and adjacencyList
variables?
I am using python 3.1.2.
Mutable default arguments don't generally do what you want. Instead, try this:
class Node:
def __init__(self, wordList=None, adjacencyList=None):
if wordList is None:
self.wordList = []
else:
self.wordList = wordList
if adjacencyList is None:
self.adjacencyList = []
else:
self.adjacencyList = adjacencyList