Sorting in a List of Dictionaries with Letters & Numbers

Question

I have a list of dictionaries that I'm trying to sort. This is what I have so far:

output_list = [{'mac': '0123.4567.89ab', 'port': 'Gi1/0/10'},
               {'mac': '0123.4567.89ab', 'port': 'Gi1/0/1'},
               {'mac': '0123.4567.89ab', 'port': 'Gi1/0/5'},
               {'mac': '0123.4567.89ab', 'port': 'Gi1/0/48'},
               {'mac': '0123.4567.89ab', 'port': 'Gi2/0/1'},
               {'mac': '0123.4567.89ab', 'port': 'Gi1/0/6'},
               {'mac': '0123.4567.89ab', 'port': 'Gi2/0/4'},
               {'mac': '0123.4567.89ab', 'port': 'Gi2/0/13'},
               {'mac': '0123.4567.89ab', 'port': 'Gi8/0/9'},
               {'mac': '0123.4567.89ab', 'port': 'Gi8/0/8'},
               {'mac': '0123.4567.89ab', 'port': 'Te1/1/1'}]

mac_list = sorted(output_list, key=lambda d: "/".join([x for x in d['port'].split("/")]))

pprint(mac_list)

However, it's not sorting the dictionaries the way I want.

"C:\Program Files\Python310\python.exe" "C:/Scripts/Python/test1.py"
[{'mac': '0123.4567.89ab', 'port': 'Gi1/0/1'},
 {'mac': '0123.4567.89ab', 'port': 'Gi1/0/10'},
 {'mac': '0123.4567.89ab', 'port': 'Gi1/0/48'},
 {'mac': '0123.4567.89ab', 'port': 'Gi1/0/5'},
 {'mac': '0123.4567.89ab', 'port': 'Gi1/0/6'},
 {'mac': '0123.4567.89ab', 'port': 'Gi2/0/1'},
 {'mac': '0123.4567.89ab', 'port': 'Gi2/0/13'},
 {'mac': '0123.4567.89ab', 'port': 'Gi2/0/4'},
 {'mac': '0123.4567.89ab', 'port': 'Gi8/0/8'},
 {'mac': '0123.4567.89ab', 'port': 'Gi8/0/9'},
 {'mac': '0123.4567.89ab', 'port': 'Te1/1/1'}]

Process finished with exit code 0

How can I get it to sort it so it looks like this:

[{'mac': '0123.4567.89ab', 'port': 'Gi1/0/1'},
 {'mac': '0123.4567.89ab', 'port': 'Gi1/0/5'},
 {'mac': '0123.4567.89ab', 'port': 'Gi1/0/6'},
 {'mac': '0123.4567.89ab', 'port': 'Gi1/0/10'},
 {'mac': '0123.4567.89ab', 'port': 'Gi1/0/48'},
 {'mac': '0123.4567.89ab', 'port': 'Gi2/0/1'},
 {'mac': '0123.4567.89ab', 'port': 'Gi2/0/4'},
 {'mac': '0123.4567.89ab', 'port': 'Gi2/0/13'},
 {'mac': '0123.4567.89ab', 'port': 'Gi8/0/8'},
 {'mac': '0123.4567.89ab', 'port': 'Gi8/0/9'},
 {'mac': '0123.4567.89ab', 'port': 'Te1/1/1'}]

See [Sorting HOW TO](https://docs.python.org/3/howto/sorting.html) in the documentation. — martineau, Jun 22 '22 at 22:58
Your calculated port key is still being compare lexicographically, not numerically. Convert it into a tuple and make the numeric portions of it integers. — martineau, Jun 22 '22 at 23:04

Andrej Kesely · Accepted Answer · 2022-06-22T23:01:50.230

Try:

out = sorted(
    output_list,
    key=lambda d: (d["port"][:2], *map(int, d["port"][2:].split("/"))),
)

print(out)

Prints:

[
    {"mac": "0123.4567.89ab", "port": "Gi1/0/1"},
    {"mac": "0123.4567.89ab", "port": "Gi1/0/5"},
    {"mac": "0123.4567.89ab", "port": "Gi1/0/6"},
    {"mac": "0123.4567.89ab", "port": "Gi1/0/10"},
    {"mac": "0123.4567.89ab", "port": "Gi1/0/48"},
    {"mac": "0123.4567.89ab", "port": "Gi2/0/1"},
    {"mac": "0123.4567.89ab", "port": "Gi2/0/4"},
    {"mac": "0123.4567.89ab", "port": "Gi2/0/13"},
    {"mac": "0123.4567.89ab", "port": "Gi8/0/8"},
    {"mac": "0123.4567.89ab", "port": "Gi8/0/9"},
    {"mac": "0123.4567.89ab", "port": "Te1/1/1"},
]

Note:

(d["port"][:2], *map(int, d["port"][2:].split("/"))) will create tuple in form ('Gi', 1, 0, 48) etc. The sorted() function will then sort according these tuples.

While this code may answer the question, it would be better to include some context, explaining _how_ it works and _when_ to use it. Code-only answers are not useful in the long run. — martineau, Jun 22 '22 at 23:00

constantstranger · Answer 2 · 2022-06-22T23:20:59.387

1

Try this:

mac_list = sorted(output_list, key=lambda d: tuple(int(x) if x.isdigit() else x for x in d['port'].split("/")))

This will convert numeric strings to int values in the substrings of the port value produced by split() and leave non-numeric strings as is, and sorting based on the resulting tuple values will get you the desired output.

edited Jun 22 '22 at 23:20

answered Jun 22 '22 at 23:01

constantstranger

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score 1 · Answer 3 · answered Jun 22 '22 at 23:06

Seems that you're looking for human/natural sorting. This answer covers it well.

Using the natural_keys function from that answer, the port string could then be passed directly to the defined function as follow:

output_list.sort(key=lambda d: natural_keys(d["port"]))

Sorting in a List of Dictionaries with Letters & Numbers

3 Answers3