Sorting using custom comparator function in python

Question

i have a list L = [['92', '022'], ['77', '13'], ['82', '12']]

want to sort on second element as key : ['022','13','12']

having to custom functions for numerically sort and lexicographically sort. but not getting the desired output...

for numerically sort output like : [['82', '12'],['77', '13'],['92', '022']]

for lexicographically sort output like : [['92', '022'],['82', '12'], ['77', '13']]

from functools import cmp_to_key

L = [['92', '022'], ['77', '13'], ['82', '12']]
key=2

def compare_num(item1,item2):
   return (int(item1[key-1]) > int(item2[key-1]))

def compare_lex(item1,item2):
   return item1[key-1]<item2[key-1]

print(sorted(l, key=cmp_to_key(compare_num)))
print(sorted(l, key=cmp_to_key(compare_lex)))

Dharman · Accepted Answer · 2020-10-13 00:48:53Z

0

Please try this - it should work:

L = [['92', '022'], ['77', '13'], ['82', '12']]

#Numerically sorted:
sorted(L, key = lambda x: x[-1])
[['92', '022'], ['82', '12'], ['77', '13']]

#Lexicographically sorted:
sorted(L, key = lambda x: int(x[-1]))
[['82', '12'], ['77', '13'], ['92', '022']]

edited Oct 13, 2020 at 0:48

Dharman♦

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answered Jul 4, 2020 at 9:54

Issei Kumagai

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Comments

Austin · Accepted Answer · 2020-07-04 09:49:22Z

0

You are making it complex. key argument can take a custom function.

l = [['92', '022'], ['77', '13'], ['82', '12']]
key = 2

def compare_num(item1):
   return int(item1[key-1])

def compare_lex(item1):
   return item1[key-1]

print(sorted(l, key=compare_num))
print(sorted(l, key=compare_lex))

answered Jul 4, 2020 at 9:49

Austin

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