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# numpy.savez

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

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

  If arguments are passed in with no keywords, the corresponding variable names, in the .npz file, are ‘arr_0’, ‘arr_1’, etc. If keyword arguments are given, the corresponding variable names, in the `.npz` file will match the keyword names.

  Parameters : | file : str or file Either the file name (string) or an open file (file-like object) where the data will be saved. If file is a string, the `.npz` extension will be appended to the file name if it is not already there. *args : Arguments, optional Arrays to save to the file. Since it is not possible for Python to know the names of the arrays outside savez, the arrays will be saved with names “arr_0”, “arr_1”, and so on. These arguments can be any expression. **kwds : Keyword arguments, optional Arrays to save to the file. Arrays will be saved in the file with the keyword names.
  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.

  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 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.

  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_1', 'arr_0']
      >>> 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)
      >>> npzfile.files
      ['y', 'x']
      >>> npzfile['x']
      array([0, 1, 2, 3, 4, 5, 6, 7, 8, 9])

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