将项目的索引附加到python中的另一个列表

Question

I used the code below to append the index of an item to another list, but it only gives the index of some previous occurrence of the same item.

for x,y in zip(answer,std_answer):
        if x != y:
           wrong_ans.append(answer.index(x))

Please i need the code to append the exact index of the item to another list. Thank you

Answer 1

for i, (x, y) in enumerate(zip(answer, std_answer)):
   if x != y
       wrong_ans.append(i)

enumerate is a built-in function that iterates over an iterable, returning the items of the iterable and the iteration index. It's both faster than index(x) , which searches your list each time it runs, and not subject to identifying earlier appearances of the value.

Answer 2

Keep it simple:

for i in range(min(len(std_answer), len(answer))):
    if answer[i] != std_answer[i]:
        wrong_ans.append(i)