# numpy.savez

numpy.savez(file, *args, **kwds)

  Save several arrays into a single file in uncompressed `.npz` format.

  Provide arrays as keyword arguments to store them under the corresponding name in the output file: `savez(fn, x=x, y=y)`.

  If arrays are specified as positional arguments, i.e., `savez(fn, x, y)`, their names will be arr_0, arr_1, etc.

  Parameters
    file str or file

      Either the filename (string) or an open file (file-like object) where the data will be saved. If file is a string or a Path, the `.npz` extension will be appended to the filename if it is not already there.

    args Arguments, optional

      Arrays to save to the file. Please use keyword arguments (see kwds below) to assign names to arrays. Arrays specified as args will be named “arr_0”, “arr_1”, and so on.

    kwds Keyword arguments, optional

      Arrays to save to the file. Each array will be saved to the output file with its corresponding keyword name.

  Returns
    None

  See also

  `save`

    Save a single array to a binary file in NumPy format.

  `savetxt`

    Save an array to a file as plain text.

  `savez_compressed`

    Save several arrays into a compressed `.npz` archive

  Notes

  The `.npz` file format is a zipped archive of files named after the variables they contain. The archive is not compressed and each file in the archive contains one variable in `.npy` format. For a description of the `.npy` format, see `numpy.lib.format`.

  When opening the saved `.npz` file with `load` a NpzFile object is returned. This is a dictionary-like object which can be queried for its list of arrays (with the `.files` attribute), and for the arrays themselves.

  Keys passed in kwds are used as filenames inside the ZIP archive. Therefore, keys should be valid filenames; e.g., avoid keys that begin with `/` or contain `.`.

  When naming variables with keyword arguments, it is not possible to name a variable `file`, as this would cause the `file` argument to be defined twice in the call to `savez`.

  Examples

      >>> from tempfile import TemporaryFile
      >>> outfile = TemporaryFile()
      >>> x = np.arange(10)
      >>> y = np.sin(x)

  Using `savez` with *args, the arrays are saved with default names.

      >>> np.savez(outfile, x, y)
      >>> _ = outfile.seek(0) # Only needed here to simulate closing & reopening file
      >>> npzfile = np.load(outfile)
      >>> npzfile.files
      ['arr_0', 'arr_1']
      >>> npzfile['arr_0']
      array([0, 1, 2, 3, 4, 5, 6, 7, 8, 9])

  Using `savez` with **kwds, the arrays are saved with the keyword names.

      >>> outfile = TemporaryFile()
      >>> np.savez(outfile, x=x, y=y)
      >>> _ = outfile.seek(0)
      >>> npzfile = np.load(outfile)
      >>> sorted(npzfile.files)
      ['x', 'y']
      >>> npzfile['x']
      array([0, 1, 2, 3, 4, 5, 6, 7, 8, 9])

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