In Python, how do I iterate over a dictionary in sorted key order?


Question

There's an existing function that ends in the following, where d is a dictionary:

return d.iteritems()

that returns an unsorted iterator for a given dictionary. I would like to return an iterator that goes through the items sorted by key. How do I do that?

1
201
12/17/2018 1:11:41 AM

Accepted Answer

Haven't tested this very extensively, but works in Python 2.5.2.

>>> d = {"x":2, "h":15, "a":2222}
>>> it = iter(sorted(d.iteritems()))
>>> it.next()
('a', 2222)
>>> it.next()
('h', 15)
>>> it.next()
('x', 2)
>>>

If you are used to doing for key, value in d.iteritems(): ... instead of iterators, this will still work with the solution above

>>> d = {"x":2, "h":15, "a":2222}
>>> for key, value in sorted(d.iteritems()):
>>>     print(key, value)
('a', 2222)
('h', 15)
('x', 2)
>>>

With Python 3.x, use d.items() instead of d.iteritems() to return an iterator.

165
12/17/2018 1:13:06 AM

Use the sorted() function:

return sorted(dict.iteritems())

If you want an actual iterator over the sorted results, since sorted() returns a list, use:

return iter(sorted(dict.iteritems()))

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