Boolean list operation in python [duplicate]

Question

Shouldn't the results be the same? I do not understand.

[True,False] and [True, True]
Out[1]: [True, True]

[True, True] and [True,False]
Out[2]: [True, False]

Answer 1

No, because that's not the way that and operation works in python. First off it doesn't and the list items separately. Secondly the and operator works between two objects and if one of them is False (evaluated as False ¹) it returns that and if both are True it returns the second one. Here is an example :

>>> [] and [False]
[]
>>> 
>>> [False] and []
[]
>>> [False] and [True]
[True]

x and y : if x is false, then x, else y

If you want to apply the logical operations on all the lists pairs you can use numpy arrays:

>>> import numpy as np
>>> a = np.array([True, False])
>>> b = np.array([True, True])
>>> 
>>> np.logical_and(a,b)
array([ True, False], dtype=bool)
>>> np.logical_and(b,a)
array([ True, False], dtype=bool)

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_{1. Here since you are dealing with lists an empty list will be evaluated as False}