Python：根据另一个列表中的元素按索引从列表中删除元素

Question

So I have a list

a_list = [0,3,4,7,9,11,15]

and a list of outliers

outliers = [0,3,4]

The outliers is the list of indexes that need to be removed from a_list

So in this case, remove the elements in index 0, 3, 4 from a_list. Result should be:

remove these = [0,7,9]
a_list = [0,3,4,11,15]

If I use the del method, the index will change so once I remove 0th index, I will still remove the 3rd index but instead remove 9 and 4th index will remove 15.

How can I remove items from a_list with the indexes specified in a separate list?

Answer 1

Compare index to outliers list. If the index is matching to outliers then skip it.

print([x for i, x in enumerate(a_list) if i not in outliers])

Better to use set(outliers) if outliers contain the duplicate elements.

Answer 2

Here is a real quick implementation based on what the others were commenting about.

a_list = [0,3,4,7,9,11,15]
outliers = [0,3,4]
outliers.reverse()
for i in outliers:
    del a_list[i]
print(a_list)

Simply call outliers.reverse() before iterating and delete as normal.