Sort a python list of strings with a numeric number

问题

I have a list of filenames called filelist

 In []: filelist
Out []: ['C:\\Mon20412\\P-2NODE-RAID6-1BLACK-32k-100-segmented.xlsx',
         'C:\\Mon25312\\P-2NODE-RAID6-13RED-32k-100-segmented.xlsx',
         'C:\\Mon20362\\P-2NODE-RAID6-2GREEN-32k-100-segmented.xlsx']

I want to sort this filelist by the numerical value that is in the bolded position

C:\Mon20412\P-2NODE-RAID6-1BLACK-32k-100-segmented.xlsx
C:\Mon25312\P-2NODE-RAID6-13RED-32k-100-segmented.xlsx
C:\Mon20362\P-2NODE-RAID6-2GREEN-32k-100-segmented.xlsx

So in this example, the output would be

Out []: ['C:\\Mon20412\\P-2NODE-RAID6-1BLACK-32k-100-segmented.xlsx',
         'C:\\Mon20362\\P-2NODE-RAID6-2GREEN-32k-100-segmented.xlsx'
         'C:\\Mon25312\\P-2NODE-RAID6-13RED-32k-100-segmented.xlsx']

Thank you!

回答1:

Find a good, reliable way to extract the number that you want. Then sort by that number, using the key argument. This seems to be reliable enough for your input, but it's not efficient.

a = ['C:\\Mon20412\\P-2NODE-RAID6-1BLACK-32k-100-segmented.xlsx',
    'C:\\Mon25312\\P-2NODE-RAID6-13RED-32k-100-segmented.xlsx',
    'C:\\Mon20362\\P-2NODE-RAID6-2GREEN-32k-100-segmented.xlsx']

def k(a):
    x = a.split("\\")[-1].split("-")[3]
    y = filter(lambda x: x in "0123456789", x)
    return int("".join(list(y)))


print(sorted(a, key=k))

output:

['C:\\Mon20412\\P-2NODE-RAID6-1BLACK-32k-100-segmented.xlsx', 
'C:\\Mon20362\\P-2NODE-RAID6-2GREEN-32k-100-segmented.xlsx',
'C:\\Mon25312\\P-2NODE-RAID6-13RED-32k-100-segmented.xlsx']

回答2:

import re

f = lambda s: int(re.findall(r'.*RAID6-(\d+).*', s)[0])
sorted(l, key=f)

回答3:

Use a regex to parse out the number and use that as a sort key.

Quick and dirty:

import re

l = ['C:\\Mon20412\\P-2NODE-RAID6-1BLACK-32k-100-segmented.xlsx',
     'C:\\Mon25312\\P-2NODE-RAID6-13RED-32k-100-segmented.xlsx',
     'C:\\Mon20362\\P-2NODE-RAID6-2GREEN-32k-100-segmented.xlsx']

def get_sort_number(s):
    pattern = r'C:\\Mon\d+\\P-2NODE-RAID6-(\d+)'

    try:
        return int(re.match(pattern, s).group(1))
    except AttributeError:
        return 0

sorted(l, key=get_sort_number)

This gives

['C:\\Mon20412\\P-2NODE-RAID6-1BLACK-32k-100-segmented.xlsx',
 'C:\\Mon20362\\P-2NODE-RAID6-2GREEN-32k-100-segmented.xlsx',
 'C:\\Mon25312\\P-2NODE-RAID6-13RED-32k-100-segmented.xlsx']

All strings that cannot be matched by the regex would be at the beginning of the sorted list.

来源：https://stackoverflow.com/questions/35142908/sort-a-python-list-of-strings-with-a-numeric-number

标签

python

string

list

sorting

numerical