Add a new item to a dictionary in Python

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Chapters
00:00 Question
00:26 Accepted answer (Score 1360)
00:45 Answer 2 (Score 93)
01:13 Answer 3 (Score 25)
01:59 Thank you

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Full question
https://stackoverflow.com/questions/6416...

Answer 1 links:
[Chris' answer]: https://stackoverflow.com/questions/6416...
[update]: http://docs.python.org/library/stdtypes....
[dictionaries as data structures]: http://docs.python.org/tutorial/datastru...
[dictionaries as built-in types]: http://docs.python.org/library/stdtypes....

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https://meta.stackexchange.com/help/lice...

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Tags
#python #dictionary #items

#avk47

ACCEPTED ANSWER

Score 1376

default_data['item3'] = 3

Easy as py.

Another possible solution:

default_data.update({'item3': 3})

which is nice if you want to insert multiple items at once.

ANSWER 2

Score 96

It can be as simple as:

default_data['item3'] = 3

As Chris' answer says, you can use update to add more than one item. An example:

default_data.update({'item4': 4, 'item5': 5})

Please see the documentation about dictionaries as data structures and dictionaries as built-in types.

ANSWER 3

Score 26

It occurred to me that you may have actually be asking how to implement the + operator for dictionaries, the following seems to work:

>>> class Dict(dict):
...     def __add__(self, other):
...         copy = self.copy()
...         copy.update(other)
...         return copy
...     def __radd__(self, other):
...         copy = other.copy()
...         copy.update(self)
...         return copy
... 
>>> default_data = Dict({'item1': 1, 'item2': 2})
>>> default_data + {'item3': 3}
{'item2': 2, 'item3': 3, 'item1': 1}
>>> {'test1': 1} + Dict(test2=2)
{'test1': 1, 'test2': 2}

Note that this is more overhead then using dict[key] = value or dict.update(), so I would recommend against using this solution unless you intend to create a new dictionary anyway.