In [1]:

    

import numpy as np


    

In [2]:

    

a_1d = np.arange(4)
print(a_1d)


    

    




[0 1 2 3]

In [3]:

    

print(a_1d[[True, False, True, False]])


    

    




[0 2]

In [4]:

    

print(a_1d[np.array([True, False, True, False])])


    

    




[0 2]

In [5]:

    

# print(a_1d[[True, False]])
# IndexError: boolean index did not match indexed array along dimension 0; dimension is 4 but corresponding boolean dimension is 2


    

In [6]:

    

a_2d = np.arange(12).reshape(3, 4)
print(a_2d)


    

    




[[ 0  1  2  3]
 [ 4  5  6  7]
 [ 8  9 10 11]]

In [7]:

    

print(a_2d[[True, False, True]])


    

    




[[ 0  1  2  3]
 [ 8  9 10 11]]

In [8]:

    

print(a_2d[:, [True, False, True, False]])


    

    




[[ 0  2]
 [ 4  6]
 [ 8 10]]

In [9]:

    

print(a_2d[[True, False, True], [True, False, True, False]])


    

    




[ 0 10]

In [10]:

    

print(a_2d[np.ix_([True, False, True], [True, False, True, False])])


    

    




[[ 0  2]
 [ 8 10]]

In [11]:

    

print(a_2d[:, [True, False, False, False]])


    

    




[[0]
 [4]
 [8]]

In [12]:

    

print(a_2d > 5)


    

    




[[False False False False]
 [False False  True  True]
 [ True  True  True  True]]

In [13]:

    

print(type(a_2d > 5))


    

    




<class 'numpy.ndarray'>

In [14]:

    

print(a_2d[a_2d > 5])


    

    




[ 6  7  8  9 10 11]

In [15]:

    

print((a_2d > 5) & (a_2d < 10))


    

    




[[False False False False]
 [False False  True  True]
 [ True  True False False]]

In [16]:

    

print(a_2d[(a_2d > 5) & (a_2d < 10)])


    

    




[6 7 8 9]