Iterate over a dictionary in sorted order in Python

This post will discuss how to iterate over a dictionary in sorted order of its keys or values in Python.

With Python 3.7, a dictionary is guaranteed to be iterated in the insertion order of keys. If you need to iterate over a dictionary in sorted order of its keys or values, you can pass the dictionary’s entries to the sorted() function, which returns a list of tuples. You can get the view on the dictionary’s entries using either dict.items() or dict.keys() function.

1. Using `dict.items()` function

A standard solution to iterate over a dictionary in sorted order of keys is using the dict.items() with sorted() function.

if __name__ == '__main__':

d = {'one': 1, 'two': 2, 'three': 3, 'four': 4}

for k, v in sorted(d.items()):

print((k, v))

'''

Output:

('four', 4)

('one', 1)

('three', 3)

('two', 2)

'''

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To iterate in reverse order of keys, you can specify the reverse argument of the sorted() function as True.

if __name__ == '__main__':

d = {'one': 1, 'two': 2, 'three': 3, 'four': 4}

for k, v in sorted(d.items(), reverse=True):

print((k, v))

'''

Output:

('two', 2)

('three', 3)

('one', 1)

('four', 4)

'''

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2. Using `dict.keys()` function

Another simple solution to iterate over a dictionary in the sorted order of keys is to use the dict.keys() with the sorted() function.

if __name__ == '__main__':

d = {'one': 1, 'two': 2, 'three': 3, 'four': 4}

for k in sorted(d.keys()):

print((k, d[k]))

'''

Output:

('four', 4)

('one', 1)

('three', 3)

('two', 2)

'''

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This is equivalent to:

if __name__ == '__main__':

d = {'one': 1, 'two': 2, 'three': 3, 'four': 4}

for k in sorted(d):

print((k, d[k]))

'''

Output:

('four', 4)

('one', 1)

('three', 3)

('two', 2)

'''

Download Run Code

Alternatively, to iterate in reverse order of keys, you can specify the reverse argument of the sorted() function as True.

if __name__ == '__main__':

d = {'one': 1, 'two': 2, 'three': 3, 'four': 4}

for k in sorted(d, reverse=True):

print((k, d[k]))

'''

Output:

('two', 2)

('three', 3)

('one', 1)

('four', 4)

'''

Download Run Code

Finally, to iterate the dictionary in sorted order of values, you can supply the key argument of the sorted() function.

if __name__ == '__main__':

d = {'three': 3, 'two': 2, 'four': 4, 'one': 1}

for k in sorted(d, key=d.get):

print((k, d[k]))

'''

Output:

('one', 1)

('two', 2)

('three', 3)

('four', 4)

'''

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If the dictionary’s values are numeric, you can also use the Counter class from the collections module to iterate over the dictionary in decreasing order of their values.

from collections import Counter

if __name__ == '__main__':

d = {'three': 3, 'two': 2, 'four': 4, 'one': 1}

c = Counter(d)

for p in c.most_common():

print(p)

'''

Output:

('four', 4)

('three', 3)

('two', 2)

('one', 1)

'''

Download Run Code

That’s all about iterating over a dictionary in sorted order in Python.

Iterate over a dictionary in sorted order in Python

1. Using dict.items() function

2. Using dict.keys() function

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1. Using `dict.items()` function

2. Using `dict.keys()` function