Navigate with the Python Client

In this tutorial we will navigate a collection of datasets using Tiled’s Python client.

To follow along, start the Tiled server with example data from a Terminal.

tiled serve pyobject --public tiled.examples.generated:tree

Now, in a Python interpreter, connect, with the Python client.

from tiled.client import from_uri

client = from_uri("http://localhost:8000")

This holds a nested structure of data. Conceptually, it corresponds well to a directory of files or hierarchical structure like an HDF5 file or XML file.

Tiled provides a utility for visualizing a nested structure.

>>> from tiled.utils import tree
>>> tree(client)
├── big_image
├── small_image
├── tiny_image
├── tiny_cube
├── tiny_hypercube
├── low_entropy
├── high_entropy
├── short_table
├── long_table
├── labeled_data
│   └── image_with_dims
└── structured_data
    ├── image_with_coords
    └── xarray_dataset

Each (sub)tree displays the names of a couple of its entries—up to however many fit on one line.

>>> client
<Node {'big_image', 'small_image', 'tiny_image', 'tiny_cube', ...} ~11 entries>

Nodes act like (nested) mappings in Python. All the (read-only) methods that work on Python dictionaries work on Nodes. We can lookup a specific value by its key

>>> client['structured_data']
<Node {'image_with_coords', 'xarray_dataset'}>

list all the keys

>>> list(client)
['big_image',
 'small_image',
 'tiny_image',
 'tiny_cube',
 'tiny_hypercube',
 'low_entropy',
 'high_entropy',
 'short_table',
 'long_table',
 'labeled_data',
 'structured_data']

and loop over keys, values, or (key, value) pairs.

for key in client:
    ...

# This is equivalent:
for key in client.keys():
    ...

for value in client.values():
    ...

for key, value in client.items():
    ...

Nodes also support efficient list-like access. This is useful for quickly looking at a couple or efficiently grabbing batches of items, especially if you need to start from the middle.

>>> client.keys().first()  # Acces the first key.
'big_image'

>>> client.keys().head()  # Access the first several keys.
['big_image',
 'small_image',
 'tiny_image',
 'tiny_cube',
 'tiny_hypercube']

>>> client.keys().head(3)  # Access the first N keys.
['big_image',
 'small_image',
 'tiny_image']

>>> client.keys()[1:3]  # Access just the keys for entries 1:3.
['small_image', 'tiny_image']

All the same methods work for values

>>> client.values()[1:3]  # Access the values (which may be more expensive).
[<ArrayClient>, <ArrayClient>]

and (key, value) pairs (“items”).

>>> client.items()[1:3]  # Access (key, value) pairs.
[('small_image', <ArrayClient>),
[('tiny_image', <ArrayClient>),

Each item has metadata, which is a simple dict. The content of this dict has no special meaning to Tiled; it’s the user’s space to use or not.

>>> client.metadata  # happens to be empty
DictView({})

>>> client['short_table'].metadata  # happens to have some stuff
DictView({'animal': 'dog', 'color': 'red'})

See a later tutorial for how to search Nodes with queries.