Debbugging - 用于修复功能

Question

I am debugging the following function:

def buggy_dedup_sort_by_len(input):
unique = list(set(input))
return unique.sort(key=len)

the list is sorted but the unique.sort(key=len) is returning nothing. wont the function list.sort return anything.How can I fix it???

Answer 1

sort returns None because it mutates the list in-place. Try:

def buggy_dedup_sort_by_len(input):
    unique = list(set(input))
    unique.sort(key=len)
    return unique

Alternatively, use sorted , which does return a list.

def buggy_dedup_sort_by_len(input):
    unique = list(set(input))
    return sorted(unique, key=len)