Data Types

This library contains various extra data types, based to a certain extend on MIT-licensed code from Peter Norvig, AI: A Modern Appproach : http://aima.cs.berkeley.edu/python/utils.html

class datatypes.FIFOQueue(data=[])

A First-In-First-Out Queue

append(item)

extend(items)

Append all elements from items to the queue

pop()

Retrieve the next element in line, this will remove it from the queue

class datatypes.PriorityQueue(data=[], f=<function <lambda> at 0x1aa65f0>, minimize=False, blockworse=False, blockequal=False)

A queue in which the maximum (or minumum) element is returned first, as determined by either an external score function f (by default calling the objects score() method). If minimize=True, the item with minimum f(x) is returned first; otherwise is the item with maximum f(x) or x.score().

blockworse can be set to true if you want to prohibit adding worse-scoring items to the queue. blockequal can be set to false if you also want to prohibit adding equally-scoring items to the queue. (Both parameters default to False)

append(item)

Adds an item to the priority queue (in the right place), returns True if successfull, False if the item was blocked (because of a bad score)

pop()

Retrieve the next element in line, this will remove it from the queue

prune(n)

prune all but the first (=best) n items

prunebyscore(score, retainequalscore=False)

Deletes all items below/above a certain score from the queue, depending on whether minimize is True or False. Note: It is recommended (more efficient) to use blockworse=True / blockequal=True instead! Preventing the addition of ‘worse’ items.

score(i)

Return the score for item x (cheap lookup), Item 0 is always the best item

class datatypes.Queue

Queue is an abstract class/interface. There are three types:

Python List: A Last In First Out Queue (no Queue object necessary). FIFOQueue(): A First In First Out Queue. PriorityQueue(lt): Queue where items are sorted by lt, (default <).

Each type supports the following methods and functions:

q.append(item) – add an item to the queue q.extend(items) – equivalent to: for item in items: q.append(item) q.pop() – return the top item from the queue len(q) – number of items in q (also q.__len()).

extend(items)

Append all elements from items to the queue