在 python 中使用自定义比较器 function 进行排序

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)))

Answer 1

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))

Answer 2

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']]