How can I sort a list of strings in ascending order of numeric part

Question

I have a list of paths which have multiple numerical parts within them, here is part of it:

'C:\Python\Python310\Scripts\mockup_test\17mm.JPG',
'C:\Python\Python310\Scripts\mockup_test\18mm.JPG',
'C:\Python\Python310\Scripts\mockup_test\19mm.JPG',
'C:\Python\Python310\Scripts\mockup_test\1mm.JPG',
'C:\Python\Python310\Scripts\mockup_test\20mm.JPG',
'C:\Python\Python310\Scripts\mockup_test\21mm.JPG',
'C:\Python\Python310\Scripts\mockup_test\29mm.JPG',
'C:\Python\Python310\Scripts\mockup_test\2mm.JPG',
'C:\Python\Python310\Scripts\mockup_test\30mm.JPG',
'C:\Python\Python310\Scripts\mockup_test\31mm.JPG',
'C:\Python\Python310\Scripts\mockup_test\38mm.JPG',
'C:\Python\Python310\Scripts\mockup_test\39mm.JPG',
'C:\Python\Python310\Scripts\mockup_test\3mm.JPG'

And using .sort() doesn't change it because it thinks it is already sorted.

Here is what it should be:

Expected result:

'C:\Python\Python310\Scripts\mockup_test\1mm.JPG',
'C:\Python\Python310\Scripts\mockup_test\2mm.JPG',
'C:\Python\Python310\Scripts\mockup_test\3mm.JPG',
'C:\Python\Python310\Scripts\mockup_test\17mm.JPG',
'C:\Python\Python310\Scripts\mockup_test\18mm.JPG',
'C:\Python\Python310\Scripts\mockup_test\19mm.JPG',
'C:\Python\Python310\Scripts\mockup_test\20mm.JPG',
'C:\Python\Python310\Scripts\mockup_test\21mm.JPG',
'C:\Python\Python310\Scripts\mockup_test\29mm.JPG',
'C:\Python\Python310\Scripts\mockup_test\30mm.JPG',
'C:\Python\Python310\Scripts\mockup_test\31mm.JPG',
'C:\Python\Python310\Scripts\mockup_test\38mm.JPG',
'C:\Python\Python310\Scripts\mockup_test\39mm.JPG'

Does anyone know how this could be achieved?

user_758174 · Answer

The following sorts a list by all the parts of string found, where consecutive digits portions are to be considered as int, and the others as str:

import re 

def split_str_int(s):
    a = re.split(r'(\d+)', s)
    a[1::2] = map(int, a[1::2])
    return a

newlist = sorted(mylist, key=split_str_int)

On your data:

>>> newlist
['C:\Python\Python310\Scripts\mockup_test\1mm.JPG',
 'C:\Python\Python310\Scripts\mockup_test\2mm.JPG',
 'C:\Python\Python310\Scripts\mockup_test\3mm.JPG',
 'C:\Python\Python310\Scripts\mockup_test\17mm.JPG',
 'C:\Python\Python310\Scripts\mockup_test\18mm.JPG',
 'C:\Python\Python310\Scripts\mockup_test\19mm.JPG',
 'C:\Python\Python310\Scripts\mockup_test\20mm.JPG',
 'C:\Python\Python310\Scripts\mockup_test\21mm.JPG',
 'C:\Python\Python310\Scripts\mockup_test\29mm.JPG',
 'C:\Python\Python310\Scripts\mockup_test\30mm.JPG',
 'C:\Python\Python310\Scripts\mockup_test\31mm.JPG',
 'C:\Python\Python310\Scripts\mockup_test\38mm.JPG',
 'C:\Python\Python310\Scripts\mockup_test\39mm.JPG']

Note also that the above will sort according to all of the parts found in the strings (both numerical and non-numerical). This is to comply with: "(...) which have multiple numerical parts".

For example:

mylist = [
    'ab6cd45',
    'ab6cd2',
    'a6cd3',
    'ab4cd60',
    'a',
]
>>> sorted(mylist, key=split_str_int)
['a', 'a6cd3', 'ab4cd60', 'ab6cd2', 'ab6cd45']

user_17507911 · Answer

I belive you data is always like in this format.

lst = ['C:\Python\Python310\Scripts\mockup_test\17mm.JPG',
'C:\Python\Python310\Scripts\mockup_test\18mm.JPG',
'C:\Python\Python310\Scripts\mockup_test\19mm.JPG',
'C:\Python\Python310\Scripts\mockup_test\1mm.JPG',
'C:\Python\Python310\Scripts\mockup_test\20mm.JPG',
'C:\Python\Python310\Scripts\mockup_test\21mm.JPG',
'C:\Python\Python310\Scripts\mockup_test\29mm.JPG',
'C:\Python\Python310\Scripts\mockup_test\2mm.JPG',
'C:\Python\Python310\Scripts\mockup_test\30mm.JPG',
'C:\Python\Python310\Scripts\mockup_test\31mm.JPG',
'C:\Python\Python310\Scripts\mockup_test\38mm.JPG',
'C:\Python\Python310\Scripts\mockup_test\39mm.JPG',
'C:\Python\Python310\Scripts\mockup_test\3mm.JPG']

key =lambda e:int(e.split('\')[-1].split('mm.')[0])
print(sorted(lst,key=key))

OUTPUT

['C:\Python\Python310\Scripts\mockup_test\1mm.JPG', 
'C:\Python\Python310\Scripts\mockup_test\2mm.JPG', 
'C:\Python\Python310\Scripts\mockup_test\3mm.JPG', 
'C:\Python\Python310\Scripts\mockup_test\17mm.JPG',
 'C:\Python\Python310\Scripts\mockup_test\18mm.JPG',
 'C:\Python\Python310\Scripts\mockup_test\19mm.JPG', 
'C:\Python\Python310\Scripts\mockup_test\20mm.JPG', 
'C:\Python\Python310\Scripts\mockup_test\21mm.JPG', 
'C:\Python\Python310\Scripts\mockup_test\29mm.JPG', 
'C:\Python\Python310\Scripts\mockup_test\30mm.JPG', 
'C:\Python\Python310\Scripts\mockup_test\31mm.JPG', 
'C:\Python\Python310\Scripts\mockup_test\38mm.JPG', 
'C:\Python\Python310\Scripts\mockup_test\39mm.JPG']

user_12263779 · Answer

You could use a library for sorting called natsort

from natsort import natsorted

lst = ['C:\Python\Python310\Scripts\mockup_test\17mm.JPG',
'C:\Python\Python310\Scripts\mockup_test\18mm.JPG',
'C:\Python\Python310\Scripts\mockup_test\19mm.JPG',
'C:\Python\Python310\Scripts\mockup_test\1mm.JPG',
'C:\Python\Python310\Scripts\mockup_test\20mm.JPG',
'C:\Python\Python310\Scripts\mockup_test\21mm.JPG',
'C:\Python\Python310\Scripts\mockup_test\29mm.JPG',
'C:\Python\Python310\Scripts\mockup_test\2mm.JPG',
'C:\Python\Python310\Scripts\mockup_test\30mm.JPG',
'C:\Python\Python310\Scripts\mockup_test\31mm.JPG',
'C:\Python\Python310\Scripts\mockup_test\38mm.JPG',
'C:\Python\Python310\Scripts\mockup_test\39mm.JPG',
'C:\Python\Python310\Scripts\mockup_test\3mm.JPG']

natsorted(lst)

This Returns:

C:\Python\Python310\Scripts\mockup_test\1mm.JPG
C:\Python\Python310\Scripts\mockup_test\2mm.JPG
C:\Python\Python310\Scripts\mockup_test\3mm.JPG
C:\Python\Python310\Scripts\mockup_test\17mm.JPG
C:\Python\Python310\Scripts\mockup_test\18mm.JPG
C:\Python\Python310\Scripts\mockup_test\19mm.JPG
C:\Python\Python310\Scripts\mockup_test\20mm.JPG
C:\Python\Python310\Scripts\mockup_test\21mm.JPG
C:\Python\Python310\Scripts\mockup_test\29mm.JPG
C:\Python\Python310\Scripts\mockup_test\30mm.JPG
C:\Python\Python310\Scripts\mockup_test\31mm.JPG
C:\Python\Python310\Scripts\mockup_test\38mm.JPG
C:\Python\Python310\Scripts\mockup_test\39mm.JPG

user_14847964 · Answer

l.sort() support custom sort function. you can achive your expect result by bellow code snippet.

l = ['C:\Python\Python310\Scripts\mockup_test\17mm.JPG',
        'C:\Python\Python310\Scripts\mockup_test\18mm.JPG',
        'C:\Python\Python310\Scripts\mockup_test\19mm.JPG',
        'C:\Python\Python310\Scripts\mockup_test\1mm.JPG',
        'C:\Python\Python310\Scripts\mockup_test\20mm.JPG',
        'C:\Python\Python310\Scripts\mockup_test\21mm.JPG',
        'C:\Python\Python310\Scripts\mockup_test\29mm.JPG',
        'C:\Python\Python310\Scripts\mockup_test\2mm.JPG',
        'C:\Python\Python310\Scripts\mockup_test\30mm.JPG',
        'C:\Python\Python310\Scripts\mockup_test\31mm.JPG',
        'C:\Python\Python310\Scripts\mockup_test\38mm.JPG',
        'C:\Python\Python310\Scripts\mockup_test\39mm.JPG',
        'C:\Python\Python310\Scripts\mockup_test\3mm.JPG']
l.sort(key=lambda x: int(x.split('\')[-1][0:-6]))
print(l)

How can I sort a list of strings in ascending order of numeric part

4 Answers