Re: How to read row_name, col_name, value format TSV into a sparse matrix?
Thomas Kluyver <[email protected]> Wed, 29 Jan 2020 09:19:12 +0000
| Newsgroups | gmane.comp.python.scientific.user |
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| Message-ID | <CAOvn4qg51-8-myaD53Ptaw5CN5KiYNpVhEE_+f6WUcPfyCS=BA@mail.gmail.com> |
Reading the csv/tsv (either with pandas or numpy) doesn't create a matrix at all. It just gives you the data as it is in the file: values with associated coordinates. Then you would use something like scipy.sparse.coo_matrix() to convert that to a sparse matrix. On Wed, 29 Jan 2020 at 08:47, Peng Yu <[email protected]> wrote: > But does pandas read_csv generate a dense matrix? (I don't find numpy > read_csv. I only find numpy.loadtxt, which also only deal with dense > matrix.) What is the purpose of read into a dense matrix then convert > it to a sparse one? Isn't it better to directly read into a sparse > matrix to save memory? Thanks. > > > https://pandas.pydata.org/pandas-docs/stable/reference/api/pandas.read_csv.html > > https://docs.scipy.org/doc/numpy-1.13.0/reference/generated/numpy.loadtxt.html > > > You can either use pandas or numpy.read_csv. If the row_name and > > col_name columns contain the indices, you can then instanciate a > > scipy.sparse matrix with sparse.coo_matrix(val, (row, col))) > > > > > https://docs.scipy.org/doc/scipy/reference/generated/scipy.sparse.coo_matrix.html#scipy-sparse-coo-matrix > > -- > Regards, > Peng > _______________________________________________ > SciPy-User mailing list > [email protected] > https://mail.python.org/mailman/listinfo/scipy-user > _______________________________________________ SciPy-User mailing list [email protected] https://mail.python.org/mailman/listinfo/scipy-user