numpy.savez — NumPy v1.11 Manual (original) (raw)
numpy.savez(file, *args, **kwds)[source]¶
Save several arrays into a single file in uncompressed .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 .npzfile 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 .npzextension 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 a single array to a binary file in NumPy format.
Save an array to a file as plain text.
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 or the Numpy Enhancement Proposalhttp://docs.scipy.org/doc/numpy/neps/npy-format.html
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])