Let
L=[-1, 3, 4, -2, 6]
be a list and
indices=np.array([1, 0, 0, 1,1], dtype=bool)
a boolean vector. I would like to set the entries of L
according to indices, e.g.
L[indices]=
an object OBJ, so that the outcome is [OBJ, 3, 4, OBJ, OBJ]
.
If possible, OBJ
should be something such that, when performing its dot product with
any sparse vector, the result is again OBJ
in a very efficient way. Something like OBJ=[]
, or None
makes any sense?
Thanks a lot for your help!
I tried L[indices]=OBJ
as if L
were an array, but i get an error.
import numpy as np
L=[-1, 3, 4, -2, 6]
indices=np.array([1, 0, 0, 1,1], dtype=bool)
[None if b else e for e,b in zip(L, indices)]
results in [None, 3, 4, None, None]
is that what you mean?