Partially load.

Use case

You have a huge file that there's no need to open.

Let's create file with some data:

data = {"a": 1, "b": 2}
dh5.save(data, DATA_FILE_PATH, overwrite=True)

Open file without loading all

Put open_on_init=False

file = dh5.load(DATA_FILE_PATH, open_on_init=False)

In this case file consist of:

DH5 (r):
 {}
Unloaded keys: {'b', 'a'}

Read a key

Use classical syntax to read a key and if it wasn't yet loaded it will be.

file["a"]