ОК, поэтому я исправил кучу проблем с отступами, областями видимости и именами вашего кода (см. Ниже), и получил следующую ошибку
hi
{'a': 0}
{'a': 0, 'c': 9999999}
{'a': 0, 'c': 9999999, 'd': 9999999}
{'a': 0, 'c': 9999999, 'd': 9999999, 'e': 9999999}
{'a': 0, 'c': 3, 'd': 9999999, 'e': 9999999}
Traceback (most recent call last):
File "dijkstras.py", line 69, in <module>
dijkstra(graph, 'a', 'd')
File "dijkstras.py", line 47, in dijkstra
unseen_nodes.pop(minNode)
KeyError: 'a'
Возможно, это поможет вам продолжить?
#! /usr/bin/env python3
# dijkstras.py
import math
# must write script to turn matrix into this form of graph
graph = {
'a': {'c': 3, 'e': 5},
'c': {'a': 3, 'd': 5},
'd': {'c': 3, 'e': 6},
'e': {'d': 6, 'a': 5}
}
# defining function
def dijkstra(graph, start, goal):
shortest_distance = {} # empty dictionary
predeccesor = {} # empty dictionary
unseen_nodes = graph # makes it run through til all are seen
path = []
# start node to next node
print(str("hi"))
for node in unseen_nodes:
shortest_distance[node] = 9999999
shortest_distance[start] = 0
print(shortest_distance)
# beefy bit of dijkstras alogrithim
while unseen_nodes:
min_node = None
for node in unseen_nodes:
if min_node is None:
min_node = node
elif shortest_distance[node] < shortest_distance[min_node]:
min_node = node
for childNode, weight in graph[min_node].items():
if weight + shortest_distance[min_node] < shortest_distance[childNode]:
shortest_distance[childNode] = weight + shortest_distance[min_node]
predeccesor[childNode] = min_node
unseen_nodes.pop(min_node)
print(shortest_distance)
# reverse stack approach to trace path
current_node = goal
while current_node != start:
try:
path.insert(0, current_node)
current_node = predeccesor[current_node]
except KeyError:
print('path not valid')
# break
path.insert(0, start)
if shortest_distance[goal] != math.inf:
# print(goal)
print('shortest distance is' + str(shortest_distance[goal]))
print('path is' + str(path))
else:
print('Something Went Wrong!')
if __name__ == '__main__': # only run if script
dijkstra(graph, 'a', 'd')