13. collection — Tools for handling collections of elements belonging to multiple parts.

This module defines the Collection class.

13.1. Classes defined in module collection

class collection.Collection(obj_type=None, keep_order=False)

A collection is a set of (int,int) tuples.

The first part of the tuple has a limited number of values and are used as the keys in a dict. The second part can have a lot of different values and is implemented as an integer array with unique values. This is e.g. used to identify a set of individual parts of one or more OpenGL actors.

Examples

>>> a = Collection()
>>> a.add(range(7),3)
>>> a.add(range(4))
>>> a.remove([2,4],3)
>>> print(a)
-1 [0 1 2 3]; 3 [0 1 3 5 6];
>>> a.add([[2,0],[2,3],[-1,7],[3,88]])
>>> print(a)
-1 [0 1 2 3 7]; 2 [0 3]; 3 [ 0  1  3  5  6 88];
>>> print(a.total())
13
>>> a[2] = [1,2,3]
>>> print(a)
-1 [0 1 2 3 7]; 2 [1 2 3]; 3 [ 0  1  3  5  6 88];
>>> a[2] = []
>>> print(a)
-1 [0 1 2 3 7]; 3 [ 0  1  3  5  6 88];
>>> a.set([[2,0],[2,3],[-1,7],[3,88]])
>>> print(a)
-1 [7]; 2 [0 3]; 3 [88];
>>> print(a.keys())
[-1  2  3]
>>> for k, i in a.singles(): print(k,i)
-1 7
2 0
2 3
3 88
>>> print([k for k in a])
[-1, 2, 3]
>>> 2 in a
True
>>> del a[2]
>>> 2 in a
False

add(data, key=-1)

Add new data to a Collection.

Parameters:

• data (array_like | Collection) – An int array with shape (ndata, 2) or (ndata,), or another Collection with the same obj_type as self. If an array with shape (ndata, 2), each row has a key value in column 0 and a data value in column 1. If an (ndata,) shaped array, all items have the same key and it has to be specified separately.

• key (int) – The key value if data is an (ndata,) shaped array. Else ignored.

• keep_order –

• separately –

• used. (or a default value will be) –

• Collection (data can also be another) –

• object (if it has the same) –

• type. –

set(data, key=-1)

Set the collection to the specified data.

This is equivalent to clearing the corresponding keys before adding.

remove(data, key=-1)

Remove data from the collection.

get(key, default=[])

Return item with given key or default.

keys()

Return a sorted array with the keys

items()

Return an iterator over (key,value) pairs.

singles()

Return an iterator over the single instances

Returns next (k, i) pair from the collection.

13.2. Functions defined in module collection

collection.uniq(data, keep_order)

Uniqify data, keeping order if needed

collection.uniq_add(a, b, keep_order)

Add to a uniq array. a is supposed to be uniq, not checked!

collection.uniq_remove(a, b, keep_order)

Remove from a uniq array. a is supposed to be uniq, not checked!