CODEWITHSUNDEEP
pythonlistsortingleaderboard
Nawra C
Nawra C

Reputation: 166

Sort strings accompanied by integers in list

I am trying to make a leaderboard. Here is a list i have :

list=['rami4\n', 'kev13\n', 'demian6\n']

I would like to be able to sort this list from highest number to smallest, or even smallest to highest, giving something like : 

list=['kev13\n', 'demian6\n', 'rami4\n']

I tried to use stuff like re.findall('\d+', list[loop])[0] but i only managed to get, out of the list, the best player. Not wanting to repeat the code for as many players as there are, does anyone have an idea ?

Upvotes: 1

Views: 54

Answers (2)

Luc Giffon
Luc Giffon

Reputation: 173

I have an other solution based on Object Oriented Programming and the overriding of the __lt__ special methods of str.

import re

class SpecialString(str):
    def __lt__(self, other):
        pattern=re.compile(r"\d+")
        return int(pattern.search(str(self)).group(0)) <  int(pattern.search(str(other)).group(0))

if __name__ == "__main__":
    listing = ['rami4\n', 'kev13\n', 'demian6\n']
    spe_list = [SpecialString(x) for x in listing]
    spe_list.sort()
    print(spe_list)

Which print to the standard output:

['rami4\n', 'demian6\n', 'kev13\n']

This method allows you to not rewrite the sort function and use the built-in one (which is probably optimized). More over, since your strings may be thinked like "specialization of the str class", the inheritance mecanism is very suitable because you keep all its properties but re-write its comparison mecanism.

Upvotes: 1

Delgan
Delgan

Reputation: 19617

You indeed have to use the re module, but also the key parameter of the sort() method.

reg = re.compile('\w*?(\d+)\\n')
lst.sort(key=lambda s: int(reg.match(s).group(1)))

It works fine using findall() as you did too:

reg = re.compile('\d+')
lst.sort(key=lambda s: int(reg.findall(s)[0]))

Note that I compile() the regular expression so it is computed once and for all rather than for each element in the list.

Upvotes: 3

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