Python: Sort a list so that 5.10 is after 5.9

Question

how would you sort a list of numbers like 5.1, 5.2, 5.3,... 5.10,5.11 in a way that doesn't put 5.10 and 5.11 after 5.1 in Python. I basically want python to realize that I don't actually mean 5.10 but section 5, subsection 10.

but 5.10 == 5.1 as float. So treat elements as strings from the start. IF you can't do that there's no way to differentiate 5.1 from 5.10 — Jean-François Fabre, Jul 03 '20 at 12:20

alani · Answer 1 · 2020-07-03T12:23:54.080

5

You could treat it in the same way as a version number, for example:

>>> from distutils.version import LooseVersion

>>> a = ["5.1", "5.10", "5.11", "5.2"]

>>> sorted(a, key=LooseVersion)
['5.1', '5.2', '5.10', '5.11']

The assumption here is that you have the data in the form of strings. (It is not meaningful to distinguish e.g. 5.1 and 5.10 as floats.)

edited Jul 03 '20 at 12:23

answered Jul 03 '20 at 12:20

alani

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I don't think we can answer better than that. – Jean-François Fabre Jul 03 '20 at 12:22

score 2 · Answer 2 · answered Jul 03 '20 at 12:29

2

There's a library called natsort which does exactly that:

from natsort import natsorted
a = ["5.1", "5.10", "5.11", "5.2"]
print(natsorted(a))
# ['5.1', '5.2', '5.10', '5.11']

answered Jul 03 '20 at 12:29

Jan

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which makes me realize that the question is a duplicate. – Jean-François Fabre Jul 03 '20 at 12:39
yes, I thought that the problem was different. And the other answer proposes something not in the original question answers too. Merge could be an option but the input is too different. – Jean-François Fabre Jul 03 '20 at 12:40

Python: Sort a list so that 5.10 is after 5.9

2 Answers2