numpy.savez_compressed(file, *args, **kwds)[source]#

Save several arrays into a single file in compressed .npz format.

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

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

filefile, str, or pathlib.Path

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.

argsArguments, 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.

kwdsKeyword arguments, optional

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


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 an uncompressed .npz file format


Load the files created by savez_compressed.


The .npz file format is a zipped archive of files named after the variables they contain. The archive is compressed with zipfile.ZIP_DEFLATED 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.


>>> test_array = np.random.rand(3, 2)
>>> test_vector = np.random.rand(4)
>>> np.savez_compressed('/tmp/123', a=test_array, b=test_vector)
>>> loaded = np.load('/tmp/123.npz')
>>> print(np.array_equal(test_array, loaded['a']))
>>> print(np.array_equal(test_vector, loaded['b']))