In [1]:

    

import numpy as np


    

In [2]:

    

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


    

    




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

In [3]:

    

print(a < 5)


    

    




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

In [4]:

    

print(a[a < 5])


    

    




[0 1 2 3 4]

In [5]:

    

print(a < 10)


    

    




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

In [6]:

    

print(a[a < 10])


    

    




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

In [7]:

    

b = a[a < 10]
print(b)


    

    




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

In [8]:

    

print(a)


    

    




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

In [9]:

    

print(a[a < 5].sum())


    

    




10

In [10]:

    

print(a[a < 5].mean())


    

    




2.0

In [11]:

    

print(a[a < 5].max())


    

    




4

In [12]:

    

print(a[a < 10].min())


    

    




0

In [13]:

    

print(a[a < 10].std())


    

    




2.8722813232690143

In [14]:

    

print(a < 5)


    

    




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

In [15]:

    

print(np.all(a < 5))


    

    




False

In [16]:

    

print(np.all(a < 5, axis=0))


    

    




[False False False False]

In [17]:

    

print(np.all(a < 5, axis=1))


    

    




[ True False False]

In [18]:

    

print(a < 10)


    

    




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

In [19]:

    

print(np.all(a < 10, axis=0))


    

    




[ True  True False False]

In [20]:

    

print(np.all(a < 10, axis=1))


    

    




[ True  True False]

In [21]:

    

print(a[:, np.all(a < 10, axis=0)])


    

    




[[0 1]
 [4 5]
 [8 9]]

In [22]:

    

print(a[np.all(a < 10, axis=1), :])


    

    




[[0 1 2 3]
 [4 5 6 7]]

In [23]:

    

print(a[np.all(a < 10, axis=1)])


    

    




[[0 1 2 3]
 [4 5 6 7]]

In [24]:

    

print(a[:, np.all(a < 5, axis=0)])


    

    




[]

In [25]:

    

print(a[np.all(a < 5, axis=1)])


    

    




[[0 1 2 3]]

In [26]:

    

print(a[np.all(a < 5, axis=1)].ndim)


    

    




2

In [27]:

    

print(a[np.all(a < 5, axis=1)].shape)


    

    




(1, 4)

In [28]:

    

print(a < 5)


    

    




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

In [29]:

    

print(np.any(a < 5))


    

    




True

In [30]:

    

print(np.any(a < 5, axis=0))


    

    




[ True  True  True  True]

In [31]:

    

print(np.any(a < 5, axis=1))


    

    




[ True  True False]

In [32]:

    

print(a[:, np.any(a < 5, axis=0)])


    

    




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

In [33]:

    

print(a[np.any(a < 5, axis=1)])


    

    




[[0 1 2 3]
 [4 5 6 7]]

In [34]:

    

print(a[~(a < 5)])


    

    




[ 5  6  7  8  9 10 11]

In [35]:

    

print(a[:, np.all(a < 10, axis=0)])


    

    




[[0 1]
 [4 5]
 [8 9]]

In [36]:

    

print(a[:, ~np.all(a < 10, axis=0)])


    

    




[[ 2  3]
 [ 6  7]
 [10 11]]

In [37]:

    

print(a[np.any(a < 5, axis=1)])


    

    




[[0 1 2 3]
 [4 5 6 7]]

In [38]:

    

print(a[~np.any(a < 5, axis=1)])


    

    




[[ 8  9 10 11]]

In [39]:

    

print(a)


    

    




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

In [40]:

    

print(np.delete(a, [0, 2], axis=0))


    

    




[[4 5 6 7]]

In [41]:

    

print(np.delete(a, [0, 2], axis=1))


    

    




[[ 1  3]
 [ 5  7]
 [ 9 11]]

In [42]:

    

print(a < 2)


    

    




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

In [43]:

    

print(np.where(a < 2))


    

    




(array([0, 0]), array([0, 1]))

In [44]:

    

print(np.where(a < 2)[0])


    

    




[0 0]

In [45]:

    

print(np.where(a < 2)[1])


    

    




[0 1]

In [46]:

    

print(np.delete(a, np.where(a < 2)[0], axis=0))


    

    




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

In [47]:

    

print(np.delete(a, np.where(a < 2)[1], axis=1))


    

    




[[ 2  3]
 [ 6  7]
 [10 11]]

In [48]:

    

print(a == 6)


    

    




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

In [49]:

    

print(np.where(a == 6))


    

    




(array([1]), array([2]))

In [50]:

    

print(np.delete(a, np.where(a == 6)))


    

    




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

In [51]:

    

print(np.delete(a, np.where(a == 6)[0], axis=0))


    

    




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

In [52]:

    

print(np.delete(a, np.where(a == 6)[1], axis=1))


    

    




[[ 0  1  3]
 [ 4  5  7]
 [ 8  9 11]]

In [53]:

    

print(a[(a < 10) & (a % 2 == 1)])


    

    




[1 3 5 7 9]

In [54]:

    

print(a[np.any((a == 2) | (a == 10), axis=1)])


    

    




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

In [55]:

    

print(a[:, ~np.any((a == 2) | (a == 10), axis=0)])


    

    




[[ 0  1  3]
 [ 4  5  7]
 [ 8  9 11]]