Sorting list of strings by substring

Question

I need to sort this list

list = ['16. Michlík', '4. and 65. Bichakhchyan', '15. Pavol']

according to first number of each string. So that output should look like this

list = ['4. and 65. Bichakhchyan', '15. Pavol', '16. Michlík']

This is what I have so far, but it does not work when there is more then one number in string

sorted(list, key=lambda x : x[:x.find(".")])

Can you guys help me, please?

score 3 · Accepted Answer · answered Mar 29 '18 at 22:28

3

You must cast the pattern to an integer, otherwise it is compared as a string.

sorted(list, key=lambda x : int(x[:x.find(".")]))

answered Mar 29 '18 at 22:28

Olivier Melançon

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score 1 · Answer 2 · answered Mar 29 '18 at 22:26

1

You can use regex:

import re
l = ['16. Michlík', '4. and 65. Bichakhchyan', '15. Pavol']
result = sorted(l, key=lambda x:int(re.findall('^\d+', x)[0]))

Output:

['4. and 65. Bichakhchyan', '15. Pavol', '16. Michlík']

answered Mar 29 '18 at 22:26

Ajax1234

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You can replace `re.findall('^\d+', x)[0]` with `re.match(r'\d+', x).group()` for some free performance. – Aran-Fey Mar 29 '18 at 22:29

score 1 · Answer 3 · answered Mar 29 '18 at 22:27

1

This is one way.

lst = ['16. Michlík', '4. and 65. Bichakhchyan', '15. Pavol']

res = sorted(lst, key=lambda x: int(x.split('.')[0]))

# ['4. and 65. Bichakhchyan', '15. Pavol', '16. Michlík']

answered Mar 29 '18 at 22:27

jpp

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Sorting list of strings by substring

3 Answers3