I have a sparse array, say:
from scipy import sparse
a = sparse.lil_matrix((2,3),)
a[0] = [1, 2, 3]
a[1, 2] = 5
so it looks like:
(0, 0) 1.0
(0, 1) 2.0
(0, 2) 3.0
(1, 2) 5.0
I was wondering - is there an easy way to flip the rows (something like numpy.fliplr equivalent)? ...so I would get the output as:
(0, 0) 3.0
(0, 1) 2.0
(0, 2) 1.0
(1, 0) 5.0
One way would be to convert the array to csr format, and then manipulate the row indices:
from scipy import sparse
a = sparse.lil_matrix((2,3),)
a[0] = [1, 2, 3]
a[1, 2] = 5
a = a.tocsr()
a.indices = -a.indices + a.shape[1] - 1
print(a)
yields
(0, 2) 1.0
(0, 1) 2.0
(0, 0) 3.0
(1, 0) 5.0