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Python Using Databases in Python Our Diary App Switching It Up

Posted by Colby Work
Colby Work
20,422 Points

Why is OrderedDict written like a list?

so I thought dictionaries are written like {key: value, key: value}, but in this video, the ordered dictionary is written as a list of tuples. Is OrderedDict general for multiple kinds of collections, and not necessarily just dictionaries? Please help me understand.

thanks.

1 Answer

Chris Freeman
MOD
Chris Freeman
Treehouse Moderator 68,441 Points
Chris Freeman
Chris Freeman
Treehouse Moderator 68,441 Points

It turns out there are many ways to specify the initial data in a dict [see docs):

To illustrate, the following examples all return a dictionary equal to {"one": 1, "two": 2, "three": 3}:

>>> a = dict(one=1, two=2, three=3)
>>> b = {'one': 1, 'two': 2, 'three': 3}
>>> c = dict(zip(['one', 'two', 'three'], [1, 2, 3]))
>>> d = dict([('two', 2), ('one', 1), ('three', 3)])
>>> e = dict({'three': 3, 'one': 1, 'two': 2})
>>> a == b == c == d == e
True

In the video Kenneth is using the style "d" above.

See docs for more on OrderedDict objects

Colby Work
Colby Work
20,422 Points

ah thank you, that makes sense. for some reason, I wasn't thinking about OrderedDict in the same way dict() works, or list(), etc... now I see it. thanks again!