When popping off values, just ignore the invalid entries. The usual solution is to mark the object as invalid and to reinsert a new value. Nonetheless, I am marking Hettinger 's answer as the good one because of the detail of other possible workarounds.Īlso, Yoshida has made a valid point in that maybe a heap as it is defined might not be the best way to store the data. It is important to say that this is significantly slower than using heapq. Like this you get closer to the behavior of heapq and you are able to modify the elements in the heap for which that heap is sorted. You can use heap.pop() to pop the first element in the heap, and heap.sort(key=lambda x: x.f, reverse=True) to sort it based on the values of the attributes.
#Python priority queue update value manual
Is there any way to do this or any workaround? EDIT (WORKAROUND PERFORMED)Įventually I have defined a simple manual heap as heap = and heap.append() the objects to it. I really need to modify the value f of the object a, which has to affect the sorting of the heap every time is needed and you cannot do this through UNVISITED.f = newvalue4 (apparently). TypeError: 'tuple' object does not support item assignment _pydevd_bundle/pydevd_exec.py", line 3, in Exec > Then I am told that this value does not admit modification: UNVISITED = newvalue4įile "/home/daniel/pycharm-2017.3.3/helpers/pydev/ Throughout my algorithm, I keep modifying any valueX from the object already in the heap whenever is needed like: for i in range(len(UNVISITED)):īecause (or so I think, please correct me if I am wrong) modifying the value f like I am doing now does not change the value that affects the sorting of the heap, I directly try to modify UNVISITED (which is the above a.f passed as a second part of the second argument when creating the heap). The object a that I push, which is instantiated from a class, has the following fields: class UNVISITEDNode():ĭef _init_(self, value1, value2, value3, value4, value5): I transform an empty list called UNVISITED into a heap, such that: UNVISITED =
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