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]:

    

a_2d[0, 0] = 100
print(a_2d)


    

    




[[100   1   2   3]
 [  4   5   6   7]
 [  8   9  10  11]]

In [4]:

    

a_2d[0] = 100
print(a_2d)


    

    




[[100 100 100 100]
 [  4   5   6   7]
 [  8   9  10  11]]

In [5]:

    

a_2d[np.ix_([False, True, True], [1, 3])] = 200
print(a_2d)


    

    




[[100 100 100 100]
 [  4 200   6 200]
 [  8 200  10 200]]

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[::2, :3])


    

    




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

In [8]:

    

print(np.arange(6).reshape(2, 3) * 100)


    

    




[[  0 100 200]
 [300 400 500]]

In [9]:

    

a_2d[::2, :3] = np.arange(6).reshape(2, 3) * 100
print(a_2d)


    

    




[[  0 100 200   3]
 [  4   5   6   7]
 [300 400 500  11]]

In [10]:

    

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


    

    




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

In [11]:

    

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


    

    




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

In [12]:

    

print(np.arange(3) * 100)


    

    




[  0 100 200]

In [13]:

    

a_2d[::2, :3] = np.arange(3) * 100
print(a_2d)


    

    




[[  0 100 200   3]
 [  4   5   6   7]
 [  0 100 200  11]]

In [14]:

    

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


    

    




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

In [15]:

    

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


    

    




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

In [16]:

    

print(np.arange(2) * 100)


    

    




[  0 100]

In [17]:

    

# a_2d[::2, :3] = np.arange(2) * 100
# ValueError: could not broadcast input array from shape (2) into shape (2,3)