Sorting list of strings based on substring in each string

Question

I have a list like below:

 a = ['e8:04:62:23:57:d0\t2462\t-55\t[WPA2-PSK-CCMP][ESS]\tTest', '00:1b:2f:48:8b:f2\t2462\t-57\t[WPA2-PSK-CCMP-preauth][ESS]\tT_test', 'e8:04:62:23:4e:70\t2437\t-61\t[WPA2-PSK-CCMP][ESS]\tT_guest', 'e8:04:62:23:57:d1\t2462\t-53\t[ESS]\t', 'e8:04:62:23:4e:71\t2437\t-56\t[ESS]\t']

I want to sort the list based on the numbers after the third tab of each element, so in this case -55, -57, -61, -53 should change list order to -53, -55, -57, -61. Any way I have tried seems very convoluted (making a list of lists and so on). Should I be using a regex/pattern to simplify this?

Anshul Goyal · Accepted Answer · 2015-06-25T11:34:43.257

6

You can pass in a custom lambda here to the sorted function to get the desired result:

>>> a = ['e8:04:62:23:57:d0\t2462\t-55\t[WPA2-PSK-CCMP][ESS]\tTest', '00:1b:2f:48:8b:f2\t2462\t-57\t[WPA2-PSK-CCMP-preauth][ESS]\tT_test', 'e8:04:62:23:4e:70\t2437\t-61\t[WPA2-PSK-CCMP][ESS]\tT_guest', 'e8:04:62:23:57:d1\t2462\t-53\t[ESS]\t', 'e8:04:62:23:4e:71\t2437\t-56\t[ESS]\t']
>>> sorted(a, key = lambda x: int(x.split("\t")[2]), reverse=True)
['e8:04:62:23:57:d1\t2462\t-53\t[ESS]\t', 'e8:04:62:23:57:d0\t2462\t-55\t[WPA2-PSK-CCMP][ESS]\tTest', 'e8:04:62:23:4e:71\t2437\t-56\t[ESS]\t', '00:1b:2f:48:8b:f2\t2462\t-57\t[WPA2-PSK-CCMP-preauth][ESS]\tT_test', 'e8:04:62:23:4e:70\t2437\t-61\t[WPA2-PSK-CCMP][ESS]\tT_guest']

edited Jun 25 '15 at 11:34

answered Jun 25 '15 at 10:46

Anshul Goyal

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1

Thank you, that is much more concise and "pythonic" than what I had done. – Paul Jun 25 '15 at 10:48
1

Don't forget to use `int`.(for get ride of lexicographicaly order) – Mazdak Jun 25 '15 at 10:49
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This solution is buggy, you must convert it to `int` read this question: http://stackoverflow.com/questions/3270680/how-does-python-compare-string-and-int – Elisha Jun 25 '15 at 10:58
Thanks I can see there is a mistake here and if I use int the solution doesn't work, it will sort them backwards from what I want with -61 first. Must add `reverse=True` as well as `int`. – Paul Jun 25 '15 at 11:06

Andrew Winterbotham · Answer 2 · 2015-06-26T11:58:04.773

1

def make_sorted_list(l):
    sorted_list = []
    sorted_vals = sorted([int(s.split('\t')[2]) for s in l], reverse=True)
    for val in sorted_vals:
        for s in l:
            if int(s.split('\t')[2]) == val:
                sorted_list.append(s)
    return sorted_list

edited Jun 26 '15 at 11:58

answered Jun 25 '15 at 14:57

Andrew Winterbotham

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7
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Sorting list of strings based on substring in each string

2 Answers2