How to merge two csr_matrix into one?
python, scipy, sparse-matrix
Solution
scipy.sparse has it's own stack-methods. You can use them directly on your sparse matrices.
import scipy.sparse as sp
a = sp.csr_matrix([[1,2,3],[4,5,6]])
b = sp.csr_matrix([[7,8,9],[10,11,12]])
c = sp.vstack((a,b)) # NOT np.vstack
Problem
I have problems using scipy.sparse.csr_matrix: for instance: ``` a = csr_matrix([[1,2,3],[4,5,6]]) b = csr_matrix([[7,8,9],[10,11,12]]) ``` how to merge them into ``` [[1,2,3],[4,5,6],[7,8,9],[10,11,12]] ``` I know a way is to transfer them into numpy array first: ``` csr_matrix(numpy.vstack((a.toarray(),b.toarray()))) ``` but it won't work when the matrix is huge and sparse, because the memory would run out. so are there any way to merge them together in csr_matrix? any answers are appreciated!