Safe metadata and multiple datasets (pure numpy basiclly pickle)

savez.py

import numpy as np

SIZE = 500000
meta = {}

first = np.random.random(SIZE)
meta["first"] = {"git id": "yay this is a string"}
second = np.random.random(SIZE)
meta["second"] = {"git id": "yay this is a string"}
third = np.random.random(SIZE)
meta["third"] = {"wo": [1, 2, 3, 4, 5], "bla": "terrow"}
np.savez_compressed("test.npz", first=first, second=second, third=third, metadata=meta)

data = np.load("test.npz", allow_pickle=True)
metadata = data["metadata"][()]  # Read a 0-dimensional array

print("Keys: %s" % data.keys())
for k in data.keys():
    if k == "metadata":
        continue
    print("Data: %s" % data[k])
    print("Attr: %s" % metadata[k].keys())
    for ak in metadata[k].keys():
        print("Attr val: %s" % metadata[k][ak])