Data

class glue.core.data.Data(label='', **kwargs)[source]

Bases: object

The basic data container in Glue.

The data object stores data as a collection of Component objects. Each component stored in a dataset must have the same shape.

Catalog data sets are stored such that each column is a distinct 1-dimensional Component.

There are several ways to extract the actual numerical data stored in a Data object:

data = Data(x=[1, 2, 3], label='data')
xid = data.id['x']

data[xid]
data.get_component(xid).data
data['x']  # if 'x' is a unique component name

Likewise, datasets support fancy indexing:

data[xid, 0:2]
data[xid, [True, False, True]]

See also: Working with Data objects

Parameters:label (str) – label for data

Extra array-like keywords are extracted into components

Attributes Summary

components All ComponentIDs in the Data
coordinate_links A list of the ComponentLinks that connect pixel and world.
derived_components The ComponentIDs for each DerivedComponent
label Convenience access to data set’s label
ndim Dimensionality of the dataset
pixel_component_ids The ComponentIDs for each pixel coordinate.
primary_components The ComponentIDs not associated with a DerivedComponent
shape Tuple of array dimensions, like numpy.ndarray.shape
size Total number of elements in the dataset.
subsets Tuple of subsets attached to this dataset
visible_components ComponentIDs for all non-hidden components.
world_component_ids The ComponentIDs for each world coordinate.

Methods Summary

add_component(component, label[, hidden]) Add a new component to this data set.
add_component_link(link[, label]) Shortcut method for generating a new DerivedComponent from a ComponentLink object, and adding it to a data set.
add_subset(subset) Assign a pre-existing subset to this data object.
broadcast(attribute) Send a DataUpdateMessage to the hub
component_ids() Equivalent to Data.components
dtype(cid) Lookup the dtype for the data associated with a ComponentID
find_component_id(label) Retrieve component_ids associated by label name.
get_component(component_id) Fetch the component corresponding to component_id.
get_pixel_component_id(axis) Return the pixel glue.core.component_id.ComponentID associated with a given axis
get_world_component_id(axis) Return the world glue.core.component_id.ComponentID associated with a given axis
join_on_key(other, cid, cid_other) Create an element mapping to another dataset, by joining on values of ComponentIDs in both datasets.
new_subset([subset, color, label]) Create a new subset, and attach to self.
register_to_hub(hub) Connect to a hub.
remove_component(component_id) Remove a component from a data set
to_dataframe([index]) Convert the Data object into a pandas.DataFrame object
update_components(mapping) Change the numerical data associated with some of the Components in this Data object.
update_id(old, new) Reassign a component to a different glue.core.component_id.ComponentID

Attributes Documentation

components

All ComponentIDs in the Data

Return type:list

A list of the ComponentLinks that connect pixel and world. If no coordinate transformation object is present, return an empty list.

derived_components

The ComponentIDs for each DerivedComponent

Return type:list
label

Convenience access to data set’s label

ndim

Dimensionality of the dataset

pixel_component_ids

The ComponentIDs for each pixel coordinate.

primary_components

The ComponentIDs not associated with a DerivedComponent

Return type:list
shape

Tuple of array dimensions, like numpy.ndarray.shape

size

Total number of elements in the dataset.

subsets

Tuple of subsets attached to this dataset

visible_components

ComponentIDs for all non-hidden components.

Return type:list
world_component_ids

The ComponentIDs for each world coordinate.

Methods Documentation

add_component(component, label, hidden=False)[source]

Add a new component to this data set.

Parameters:
Raises:

TypeError, if label is invalid ValueError if the component has an incompatible shape
Returns:

The ComponentID associated with the newly-added component

Shortcut method for generating a new DerivedComponent from a ComponentLink object, and adding it to a data set.

Parameters:
Returns:

The DerivedComponent that was added
add_subset(subset)[source]

Assign a pre-existing subset to this data object.

Parameters:subset – A Subset or SubsetState object

If input is a SubsetState, it will be wrapped in a new Subset automatically

Note

The preferred way for creating subsets is via new_subset_group(). Manually-instantiated subsets will not be represented properly by the UI

broadcast(attribute)[source]

Send a DataUpdateMessage to the hub

Parameters:attribute (string) – Name of an attribute that has changed (or None)
component_ids()[source]

Equivalent to Data.components

dtype(cid)[source]

Lookup the dtype for the data associated with a ComponentID

find_component_id(label)[source]

Retrieve component_ids associated by label name.

Parameters:label – ComponentID or string to search for
Returns:The associated ComponentID if label is found and unique, else None
get_component(component_id)[source]

Fetch the component corresponding to component_id.

Parameters:component_id – the component_id to retrieve
get_pixel_component_id(axis)[source]

Return the pixel glue.core.component_id.ComponentID associated with a given axis

get_world_component_id(axis)[source]

Return the world glue.core.component_id.ComponentID associated with a given axis

join_on_key(other, cid, cid_other)[source]

Create an element mapping to another dataset, by joining on values of ComponentIDs in both datasets.

This join allows any subsets defined on other to be propagated to self.

Parameters:
Example: 
>>> d1 = Data(x=[1, 2, 3, 4, 5], k1=[0, 0, 1, 1, 2], label='d1')
>>> d2 = Data(y=[2, 4, 5, 8, 4], k2=[1, 3, 1, 2, 3], label='d2')
>>> d2.join_on_key(d1, 'k2', 'k1')

>>> s = d1.new_subset()
>>> s.subset_state = d1.id['x'] > 2
>>> s.to_mask()
array([False, False,  True,  True,  True], dtype=bool)

>>> s = d2.new_subset()
>>> s.subset_state = d1.id['x'] > 2
>>> s.to_mask()
array([ True, False,  True,  True, False], dtype=bool)

The subset state selects the last 3 items in d1. These have key values k1 of 1 and 2. Thus, the selected items in d2 are the elements where k2 = 1 or 2.

new_subset(subset=None, color=None, label=None, **kwargs)[source]

Create a new subset, and attach to self.

Note

The preferred way for creating subsets is via new_subset_group(). Manually-instantiated subsets will not be represented properly by the UI

Parameters:subset – optional, reference subset or subset state. If provided, the new subset will copy the logic of this subset.
Returns:The new subset object
register_to_hub(hub)[source]

Connect to a hub.

This method usually doesn’t have to be called directly, as DataCollections manage the registration of data objects

remove_component(component_id)[source]

Remove a component from a data set

Parameters:component_id (ComponentID) – the component to remove
to_dataframe(index=None)[source]

Convert the Data object into a pandas.DataFrame object

Parameters:index – Any ‘index-like’ object that can be passed to the pandas.Series constructor
Returns:pandas.DataFrame
update_components(mapping)[source]

Change the numerical data associated with some of the Components in this Data object.

All changes to component numerical data should use this method, which broadcasts the state change to the appropriate places.

Parameters:mapping – A dict mapping Components or ComponenIDs to arrays.
This method has the following restrictions:
  • New compoments must have the same shape as old compoments
  • Component subclasses cannot be updated.
update_id(old, new)[source]

Reassign a component to a different glue.core.component_id.ComponentID

Parameters: