numpy.savez¶

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 variablenames, in the.npz file, are ‘arr_0’, ‘arr_1’, etc. If keywordarguments 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 or a Path, the.npz extension will be appended to the file name if it is notalready there. args : Arguments, optional Arrays to save to the file. Since it is not possible for Python toknow the names of the arrays outsidesavez, the arrays will be savedwith names “arr_0”, “arr_1”, and so on. These arguments can be anyexpression. kwds : Keyword arguments, optional Arrays to save to the file. Arrays will be saved in the file with thekeyword 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.

savez_compressed

Save several arrays into a compressed.npz archive

Notes

The.npz file format is a zipped archive of files named after thevariables they contain. The archive is not compressed and each filein the archive contains one variable in.npy format. For adescription of the.npy format, seenumpy.lib.format or theNumPy Enhancement Proposalhttp://docs.scipy.org/doc/numpy/neps/npy-format.html

When opening the saved.npz file withload aNpzFile object isreturned. This is a dictionary-like object which can be queried forits list of arrays (with the.files attribute), and for the arraysthemselves.

Examples

>>>fromtempfileimportTemporaryFile>>>outfile=TemporaryFile()>>>x=np.arange(10)>>>y=np.sin(x)

Usingsavez 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])

Usingsavez 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])