In [1]:

    

from scipy.sparse import csr_matrix, lil_matrix


    

In [2]:

    

l = [[0, 10, 20],
     [30, 0, 0],
     [0, 0, 0]]


    

In [3]:

    

csr = csr_matrix(l)
print(csr)


    

    




  (0, 1)	10
  (0, 2)	20
  (1, 0)	30

In [4]:

    

print(type(csr))


    

    




<class 'scipy.sparse.csr.csr_matrix'>

In [5]:

    

lil = csr.tolil()
print(lil)


    

    




  (0, 1)	10
  (0, 2)	20
  (1, 0)	30

In [6]:

    

print(type(lil))


    

    




<class 'scipy.sparse.lil.lil_matrix'>

In [7]:

    

lil = lil_matrix(csr)
print(lil)


    

    




  (0, 1)	10
  (0, 2)	20
  (1, 0)	30

In [8]:

    

print(type(lil))


    

    




<class 'scipy.sparse.lil.lil_matrix'>

In [9]:

    

lil[0, 0] = 100


    

In [10]:

    

print(lil.toarray())


    

    




[[100  10  20]
 [ 30   0   0]
 [  0   0   0]]

In [11]:

    

print(csr.toarray())


    

    




[[ 0 10 20]
 [30  0  0]
 [ 0  0  0]]

In [12]:

    

lil2 = lil_matrix(lil)
print(lil2.toarray())


    

    




[[100  10  20]
 [ 30   0   0]
 [  0   0   0]]

In [13]:

    

lil[0, 0] = 0


    

In [14]:

    

print(lil2.toarray())


    

    




[[ 0 10 20]
 [30  0  0]
 [ 0  0  0]]

In [15]:

    

lil2_copy = lil_matrix(lil, copy=True)
print(lil2_copy.toarray())


    

    




[[ 0 10 20]
 [30  0  0]
 [ 0  0  0]]

In [16]:

    

lil[0, 0] = 100


    

In [17]:

    

print(lil2_copy.toarray())


    

    




[[ 0 10 20]
 [30  0  0]
 [ 0  0  0]]