I have this situation:
main_list = [12, 10, 30, 10, 11,10, 31]
get_indices = [1, 0, 1, 1, 0, 0, 0]
What I want to do is, extract elements from main_list according to the boolean value in get_indices.
I tried the following but it is not working :
result = main_list[bool(get_indices)]
print result
10
It should be 12, 30, 10
I just came across compress() which is best suited for this task.
compress() generates an iterator for efficient looping.
from itertools import compress
main_list = [12, 10, 30, 10, 11,10, 31]
get_indices = [1, 0, 1, 1, 0, 0, 0]
print list(compress(main_list, get_indices))
[12, 30, 10]
You can use list comprehension -
result = [x for i, x in enumerate(main_list) if get_indices[i]]
You do not need to use bool() , 0 is considered False-like in boolean context, and anything non-zero is True-like.
Example/Demo -
>>> main_list = [12, 10, 30, 10, 11,10, 31]
>>> get_indices = [1, 0, 1, 1, 0, 0, 0]
>>> result = [x for i, x in enumerate(main_list) if get_indices[i]]
>>> result
[12, 30, 10]
Or if you really want something similar to your method, since you say -
But if I was able to get my method working, I could also do for example : result = main_list[~bool(get_indices)] to get : [10, 11, 10, 31]
You can use numpy , convert the lists to numpy arrays. Example -
In [30]: import numpy as np
In [31]: main_list = [12, 10, 30, 10, 11,10, 31]
In [32]: get_indices = [1, 0, 1, 1, 0, 0, 0]
In [33]: main_array = np.array(main_list)
In [34]: get_ind_array = np.array(get_indices).astype(bool)
In [35]: main_array[get_ind_array]
Out[35]: array([12, 30, 10])
In [36]: main_array[~get_ind_array]
Out[36]: array([10, 11, 10, 31])
() around (x for i,x in enumerate(main_list)); then it's clear what's the thing that get's first generated before getting checked with if ... Just imagine that, though; won't work as real code.
result = main_list[~bool(get_indices)] to get : [10, 11, 10, 31]
numpy . Updated answer with example for that.