Use list as dictionary value using append() Python method


I have some dictionary in python, and I want to assign a list as a value to each key in the dictionary, but I need to use the append() method to add elements, but after adding the elements to the list, the value of the key is None.


dic = {}
lista = []
dic['a'] = lista.append('a')
print dic


How do I solve this problem?


The append method does not return a value, so its key has a value of None . The correct way is as follows:

>>> dic = {}
>>> lista = []
>>> dic['a'] = lista
>>> lista.append('a')
>>> print dic
{'a': ['a']}

Or, if you prefer, this way is more direct:

>>> dic = {}
>>> dic['a'] = []
>>> dic['a'].append('a')
>>> print dic
{'a': ['a']}
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