In [1]:

    

import numpy as np


    

In [2]:

    

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


    

    




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

In [3]:

    

print(a_2d[1, 1:3])


    

    




[5 6]

In [4]:

    

print(a_2d[1, [False, True, True, False]])


    

    




[5 6]

In [5]:

    

print(a_2d[1, [1, 2]])


    

    




[5 6]

In [6]:

    

print(a_2d[1:3, 1:3])


    

    




[[ 5  6]
 [ 9 10]]

In [7]:

    

print(a_2d[1:3, [False, True, True, False]])


    

    




[[ 5  6]
 [ 9 10]]

In [8]:

    

print(a_2d[1:3, [1, 2]])


    

    




[[ 5  6]
 [ 9 10]]

In [9]:

    

print(a_2d[np.ix_([1, 2], [False, True, True, False])])


    

    




[[ 5  6]
 [ 9 10]]

In [10]:

    

a_3d = np.arange(24).reshape(2, 3, 4)
print(a_3d)


    

    




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

 [[12 13 14 15]
  [16 17 18 19]
  [20 21 22 23]]]

In [11]:

    

print(a_3d[:, :2, [True, False, True, False]])


    

    




[[[ 0  2]
  [ 4  6]]

 [[12 14]
  [16 18]]]

In [12]:

    

print(a_3d[:, :2, [0, 2]])


    

    




[[[ 0  2]
  [ 4  6]]

 [[12 14]
  [16 18]]]

In [13]:

    

print(a_3d[:, [0, 2], [0, 2]])


    

    




[[ 0 10]
 [12 22]]

In [14]:

    

# print(a_3d[np.ix_(:, [0, 2], [0, 2])])
# SyntaxError: invalid syntax


    

In [15]:

    

print(a_3d[np.ix_(range(2), [0, 2], [0, 2])])


    

    




[[[ 0  2]
  [ 8 10]]

 [[12 14]
  [20 22]]]

In [16]:

    

print(a_3d[np.ix_(range(a_3d.shape[0]), [0, 2], [0, 2])])


    

    




[[[ 0  2]
  [ 8 10]]

 [[12 14]
  [20 22]]]

In [17]:

    

# print(a_3d[np.ix_(0, [0, 2], [0, 2])])
# ValueError: Cross index must be 1 dimensional


    

In [18]:

    

print(a_3d[np.ix_([0], [0, 2], [0, 2])])


    

    




[[[ 0  2]
  [ 8 10]]]