Chaining .reverse with .index on a List
This code fails when attempting to combine .reverse and .index methods on a list:
k = ['F', ' ', 'B', 'F'] def solution(formation): return ((formation.index(bCamel) > (len(formation) - 1 - (formation.reverse()).index(fCamel)))) solution(k)
The issue arises because .reverse returns None, effectively making it impossible to chain .index on the reversed list.
Avoiding Separate Reverse Statements
To avoid using a separate statement for reversing the list before indexing, you can use slicing to obtain the reversed list:
formation[::-1]
This returns a new copy of the list in reverse order, preserving the original order within the existing list.
With this adjustment, the corrected solution becomes:
k = ['F', ' ', 'B', 'F'] def solution(formation): return ((formation.index(bCamel) > (len(formation) - 1 - (formation[::-1]).index(fCamel)))) solution(k)
This code successfully uses the reversed list to compare the positions of fCamel and bCamel within the formation without modifying the original list.
The above is the detailed content of How to Reverse a List and Find an Element's Index Without Modifying the Original List?. For more information, please follow other related articles on the PHP Chinese website!