sub-list extraction, logical indexation

[Terry Reedy]

Pierre wrote:
> Hello Everyone,
> 
> I would like to know if it is possible to extract a sub-list from a
> list ?
> 
> typically if :
> 
> L =[[1, 2, 3],[4, 5, 6],[3] ]
> 
> How to extract easily the elements 0 and 2 of L in order to get :
> 
> L2 =[[1, 2, 3],[3] ]

L2 = [L[0],L[2]]
> 
> Moreover, I would like to know if it is possible to use logical
> indexation such that :
> 
> index = [ True, False, True]
> L2 = L

use zip(index,L) in a for loop
> 
> or usual indexation, something like
> index=[0, 2]
> L2 = L

#untried
L2=[]
for i in index
L2.append(L[i])

tjr