通过包含在具有相同大小的另一个列表中的索引，用较小列表中的值填充 python 中的列表？

Question

I have a list full of indexes named g_index, I have another list of the same size,named fill_list, full of values. I also have another list, P1, that is longer than g_index and fill_list. I want to create a new list of size, P1, that has the value of fill_list in the indexes of g_index, with the rest of the values being therefore, None. Note that the items in fill_list will fill the indexes in g index in a sequential order. This means that the first item of fill_list will go on index 3 of the new list ( I call it finaList in the code) and so on and so forth. The size of the list created should be the size of P1, with the values of fill_list in indexes denoted by g_index. Here is what I have:

g_index=[3,6,2,83,7,100,5,1]
fill_list=["lk",3,6,9,"gh",4,7,34]
finalList=[]
for index in range(len(P1)):
   for j in range(len(g_index)):
      if index== g_index[j]:
         finalList.append(fill_list)
print finalist

In my code, the final list just keeps appending itself with values, which is not what I am looking for.

Answer 1

What about something like this:

final_list = []

for i in range(len(P1)):
    if i in g_index:
        final_list.append(fill_list)
    else:
        final_list.append(None)

In the above example, whatever could be the whole final_list, or an item from fill_list.

Answer 2

You can create a list with None (or anything else) and then map the values like this:

g_index=[3,6,2,83,7,100,5,1]
fill_list=["lk",3,6,9,"gh",4,7,34]
p1 = [None] * (max(g_index) + 1)
for k, v in enumerate(g_index):
    p1[v] = fill_list[k]
print(p1)