NDCollection

class ndcube.NDCollection(key_data_pairs, aligned_axes=None, meta=None, **kwargs)

Bases: dict

A class for holding and manipulating a collection of aligned NDCube or NDCubeSequences.

Parameters

• data (sequence of tuple`s of (`str, NDCube or NDCubeSequence)) – The names and data cubes/sequences to held in the collection.

• aligned_axes (tuple of int, tuple of tuple`s of `int, ‘all’, or None, optional) – Axes of each cube/sequence that are aligned in numpy order. If elements are int, then the same axis numbers in all cubes/sequences are aligned. If elements are tuples of ints, then must be one tuple for every cube/sequence. Each element of each tuple gives the axes of each cube/sequence that are aligned. If ‘all’, all axes are aligned in natural order, i.e. the 0th axes of all cubes are aligned, as are the 1st, and so on. Default=None

• meta (dict, optional) – General metadata for the overall collection.

Example

Say the collection holds two NDCubes, each of 3 dimensions. aligned_axes = (1, 2) means that axis 1 (0-based counting) of cube0 is aligned with axis 1 of cube1, and axis 2 of cube0 is aligned with axis 2 of cube1. However, if aligned_axes = ((0, 1), (2, 1)) then the first tuple corresponds to cube0 and the second with cube1. This is interpretted as axis 0 of cube0 is aligned with axis 2 of cube1 while axis 1 of cube0 is aligned with axis 1 of cube1.

Attributes Summary

aligned_dimensions	Returns the lengths of all aligned axes.
aligned_world_axis_physical_types	Returns the physical types of the aligned axes of an ND object in the collection.

Methods Summary

copy()
pop(k[,d])	If key is not found, default is returned if given, otherwise KeyError is raised
popitem()	Remove and return a (key, value) pair as a 2-tuple.
setdefault()	Insert key with a value of default if key is not in the dictionary.
update(*args)	Merges a new collection with current one replacing objects with common keys.

Attributes Documentation

aligned_dimensions

Returns the lengths of all aligned axes.

If there are no aligned axes, returns None.

aligned_world_axis_physical_types

Returns the physical types of the aligned axes of an ND object in the collection.

If there are no aligned axes, returns None.

Methods Documentation

copy() → a shallow copy of D

pop(k[, d]) → v, remove specified key and return the corresponding value.

If key is not found, default is returned if given, otherwise KeyError is raised

popitem()

Remove and return a (key, value) pair as a 2-tuple.

Pairs are returned in LIFO (last-in, first-out) order. Raises KeyError if the dict is empty.

setdefault()

Insert key with a value of default if key is not in the dictionary.

Return the value for key if key is in the dictionary, else default.

update(*args)

Merges a new collection with current one replacing objects with common keys.

Takes either a single input (NDCollection) or two inputs (sequence of key/value pair and aligned axes associated with each key/value pair.