在给定索引处将给定值分配给列表的元素

Question

Given some inputs

L=[0]*5

L1=[2,3]
L2=[12,13]

my required result is:

L=[0,0,12,13,0]

I know how to get this by "brute-force", but my question is, is there a "Pythonic" way to get it, eg with a list comprehension?

Answer 1

Try this:

import numpy as np

L=np.zeros(5)
L1=np.array([2,3])
L2=np.array([12,13])

L[L1] = L2

print L
# array([  0.,   0.,  12.,  13.,   0.])

Answer 2

Not sure if this is enough pythonic for you:

>>> for i,j in enumerate(L1):
...    L[j]=L2[i]
...
>>> L
[0, 0, 12, 13, 0]

and using list comprehension:

>>> [L[i] if i not in L1 else L2[L1.index(i)] for i in range(len(L))]
[0, 0, 12, 13, 0]

Answer 3

我认为这不是pythonic，但这是列表理解。

[l.__setitem__(i, l2.pop(0)) for i in l1]