python - Convert Pandas dataframe to Sparse Numpy Matrix directly

Question

I am creating a matrix from a Pandas dataframe as follows:

dense_matrix = np.array(df.as_matrix(columns = None), dtype=bool).astype(np.int)

And then into a sparse matrix with:

sparse_matrix = scipy.sparse.csr_matrix(dense_matrix)

Is there any way to go from a df straight to a sparse matrix?

Thanks in advance.

Answer 1

df.values is a numpy array, and accessing values that way is always faster than np.array.

scipy.sparse.csr_matrix(df.values)

You might need to take the transpose first, like df.values.T. In DataFrames, the columns are axis 0.