# scipy.sparse.csc_matrix¶

class scipy.sparse.csc_matrix(arg1, shape=None, dtype=None, copy=False)[source]

Compressed Sparse Column matrix

This can be instantiated in several ways:

csc_matrix(D)
with a dense matrix or rank-2 ndarray D
csc_matrix(S)
with another sparse matrix S (equivalent to S.tocsc())
csc_matrix((M, N), [dtype])
to construct an empty matrix with shape (M, N) dtype is optional, defaulting to dtype=’d’.
csc_matrix((data, (row_ind, col_ind)), [shape=(M, N)])
where data, row_ind and col_ind satisfy the relationship a[row_ind[k], col_ind[k]] = data[k].
csc_matrix((data, indices, indptr), [shape=(M, N)])
is the standard CSC representation where the row indices for column i are stored in indices[indptr[i]:indptr[i+1]] and their corresponding values are stored in data[indptr[i]:indptr[i+1]]. If the shape parameter is not supplied, the matrix dimensions are inferred from the index arrays.

Notes

Sparse matrices can be used in arithmetic operations: they support addition, subtraction, multiplication, division, and matrix power.

• efficient arithmetic operations CSC + CSC, CSC * CSC, etc.
• efficient column slicing
• fast matrix vector products (CSR, BSR may be faster)
• slow row slicing operations (consider CSR)
• changes to the sparsity structure are expensive (consider LIL or DOK)

Examples

>>> import numpy as np
>>> from scipy.sparse import csc_matrix
>>> csc_matrix((3, 4), dtype=np.int8).toarray()
array([[0, 0, 0, 0],
[0, 0, 0, 0],
[0, 0, 0, 0]], dtype=int8)

>>> row = np.array([0, 2, 2, 0, 1, 2])
>>> col = np.array([0, 0, 1, 2, 2, 2])
>>> data = np.array([1, 2, 3, 4, 5, 6])
>>> csc_matrix((data, (row, col)), shape=(3, 3)).toarray()
array([[1, 0, 4],
[0, 0, 5],
[2, 3, 6]])

>>> indptr = np.array([0, 2, 3, 6])
>>> indices = np.array([0, 2, 2, 0, 1, 2])
>>> data = np.array([1, 2, 3, 4, 5, 6])
>>> csc_matrix((data, indices, indptr), shape=(3, 3)).toarray()
array([[1, 0, 4],
[0, 0, 5],
[2, 3, 6]])


Attributes

 nnz Get the count of explicitly-stored values (nonzeros) :Parameters: axis : {None, 0, 1}, optional Select between the number of values across the whole matrix, in each column, or in each row. has_sorted_indices Determine whether the matrix has sorted indices
 dtype (dtype) Data type of the matrix shape (2-tuple) Shape of the matrix ndim (int) Number of dimensions (this is always 2) data Data array of the matrix indices CSC format index array indptr CSC format index pointer array

Methods

 arcsin() Element-wise arcsin. arcsinh() Element-wise arcsinh. arctan() Element-wise arctan. arctanh() Element-wise arctanh. asformat(format) Return this matrix in a given sparse format asfptype() Upcast matrix to a floating point format (if necessary) astype(t) ceil() Element-wise ceil. check_format([full_check]) check whether the matrix format is valid conj() conjugate() copy() deg2rad() Element-wise deg2rad. diagonal() Returns the main diagonal of the matrix dot(other) Ordinary dot product .. eliminate_zeros() Remove zero entries from the matrix expm1() Element-wise expm1. floor() Element-wise floor. getH() get_shape() getcol(i) Returns a copy of column i of the matrix, as a (m x 1) CSC matrix (column vector). getformat() getmaxprint() getnnz([axis]) Get the count of explicitly-stored values (nonzeros) :Parameters: axis : {None, 0, 1}, optional Select between the number of values across the whole matrix, in each column, or in each row. getrow(i) Returns a copy of row i of the matrix, as a (1 x n) CSR matrix (row vector). log1p() Element-wise log1p. max([axis]) Maximum of the elements of this matrix. maximum(other) mean([axis]) Average the matrix over the given axis. min([axis]) Minimum of the elements of this matrix. minimum(other) multiply(other) Point-wise multiplication by another matrix, vector, or scalar. nonzero() nonzero indices power(n[, dtype]) This function performs element-wise power. prune() Remove empty space after all non-zero elements. rad2deg() Element-wise rad2deg. reshape(shape) rint() Element-wise rint. set_shape(shape) setdiag(values[, k]) Set diagonal or off-diagonal elements of the array. sign() Element-wise sign. sin() Element-wise sin. sinh() Element-wise sinh. sort_indices() Sort the indices of this matrix in place sorted_indices() Return a copy of this matrix with sorted indices sqrt() Element-wise sqrt. sum([axis]) Sum the matrix over the given axis. sum_duplicates() Eliminate duplicate matrix entries by adding them together tan() Element-wise tan. tanh() Element-wise tanh. toarray([order, out]) See the docstring for spmatrix.toarray. tobsr([blocksize]) tocoo([copy]) Return a COOrdinate representation of this matrix When copy=False the index and data arrays are not copied. tocsc([copy]) tocsr() todense([order, out]) Return a dense matrix representation of this matrix. todia() todok() tolil() transpose([copy]) trunc() Element-wise trunc.

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