In [1]:

    

from scipy.sparse import csr_matrix, csc_matrix, coo_matrix, lil_matrix


    

In [2]:

    

l = [[1, 0, 0, 0],
     [0, 2, 0, 0],
     [0, 0, 3, 0],
     [0, 0, 0, 4]]


    

In [3]:

    

csr = csr_matrix(l)
csc = csc_matrix(l)
coo = coo_matrix(l)
lil = lil_matrix(l)


    

In [4]:

    

print(csr[1, 1])


    

    




2

In [5]:

    

print(csc[1, 1])


    

    




2

In [6]:

    

print(lil[1, 1])


    

    




2

In [7]:

    

# print(coo[1, 1])
# TypeError: 'coo_matrix' object is not subscriptable


    

In [8]:

    

lil[0, 0] = 10
lil[0, 1] = 100


    

In [9]:

    

print(lil)


    

    




  (0, 0)	10
  (0, 1)	100
  (1, 1)	2
  (2, 2)	3
  (3, 3)	4

In [10]:

    

print(lil.toarray())


    

    




[[ 10 100   0   0]
 [  0   2   0   0]
 [  0   0   3   0]
 [  0   0   0   4]]

In [11]:

    

lil[1, 1] = 0


    

In [12]:

    

print(lil)


    

    




  (0, 0)	10
  (0, 1)	100
  (2, 2)	3
  (3, 3)	4

In [13]:

    

print(lil.toarray())


    

    




[[ 10 100   0   0]
 [  0   0   0   0]
 [  0   0   3   0]
 [  0   0   0   4]]

In [14]:

    

csr[0, 0] = 10


    

In [15]:

    

# csr[0, 1] = 100
# SparseEfficiencyWarning: Changing the sparsity structure of a csr_matrix is expensive. lil_matrix is more efficient.


    

In [16]:

    

csr[1, 1] = 0


    

In [17]:

    

print(csr)


    

    




  (0, 0)	10
  (1, 1)	0
  (2, 2)	3
  (3, 3)	4

In [18]:

    

print(csr.toarray())


    

    




[[10  0  0  0]
 [ 0  0  0  0]
 [ 0  0  3  0]
 [ 0  0  0  4]]