How to sort a list of dictionaries?

Question

If I had a list of dictionaries:

[{'name':a,  'number':b,  'blah':c,  'swag':d},
 {'name':a_1,'number':b_1,'blah':c_1,'sw‌ag':d_1},
 {'name':a_2,'number':b_2,'blah':c_2,'swag':d_2}]

How would I print all the 'name' values in alphabetical order and the 'number' values in descending order? And let's say the 'a' values are strings, and the 'b' values are integers. How would I print all the 'name' values in alphabetical order and the 'number' values in descending order?

These are not python dictionaries {a,b,c,d}. Dictionaries are {key:value} pairs. — Tanveer Alam, Nov 20 '14 at 03:38
So you are expecting two results of your lists? one based on 'a' that is string and another i.e 'b' based on integer. — Tanveer Alam, Nov 20 '14 at 03:44
possible duplicate of [How do I sort a list of dictionaries by values of the dictionary in Python?](http://stackoverflow.com/questions/72899/how-do-i-sort-a-list-of-dictionaries-by-values-of-the-dictionary-in-python) — Kevin Brown-Silva, Nov 20 '14 at 03:45
if you update with actual data, put integers, it will easy for us — Hackaholic, Nov 20 '14 at 03:46

score 1 · Answer 1 · answered Nov 20 '14 at 04:03

You can sort a list using the builtin "sorted" function. And you can extract the names and the numbers using list comprehension. Combining the two:

>>> dict_list = [{'name':a,'number':b,'blah':c,'swag':d},{'name':a_1,'number':b_1,'blah':c_1,'sw\U+200Cag':d_1},{'name':a_2,'number':b_2,'blah':c_2,'swag':d_2}]
>>> sorted_names = sorted([d['name'] for d in dict_list])
>>> sorted_names
['a', 'a_1', 'a_2']
>>> sorted_numbers = sorted([d['number'] for d in dict_list], reverse=True)
>>> sorted_numbers
[3, 2, 1]

score 0 · Answer 2 · answered Nov 20 '14 at 04:53

To sort the dict by 'name' in ascending/alphabetical order and then (for those dict who have the same 'name') by 'number' in descending order,

first sort 'number' in descending order

list_of_dict_by_numbers = sorted(original_list_of_dict, key=lambda d: d['number'], reverse=True)

or

list_of_dict_by_numbers = sorted(original_list_of_dict, key=lambda d: -d['number'])

Then sort 'name' in ascending/alphabetical order

result = sorted(list_of_dict_by_numbers, key=lambda d: d['name'])

Since python sort is stable, those dict records who have the same 'name' will retain their 'number' in the sorted descending order.

How to sort in Python

score 0 · Answer 3 · answered Nov 20 '14 at 06:41

0

Check the documentation for Python's sorted function:

https://wiki.python.org/moin/HowTo/Sorting

Make sure to read the part about keys!

answered Nov 20 '14 at 06:41

user3689258

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How to sort a list of dictionaries?

3 Answers3