costs = [ [0, [(4,2),(1,4),(5,8)], "home"], [1, [(0,4),(4,6),(2,10)], None], [2, [(3,3),(1,10)], None], [3, [(2,3),(4,4),(5,5)], "work"], [4, [(0,2),(3,4),(1,6)], None], [5, [(3,5),(0,8)], "shopping"] ] Note: •The cost data is a list of lists. It defines outbound connections between nodes. (source node (row ID) to destination node.) •In each row: 1. The first item is a row index (node ID). It is redundant and not used. It is there to make the data easier for humans to read. 2. Next is a list of tuples. They are a list of outbound connections (node and cost). •The tuple's first item is a destination node id. •The tuple's second item is the connection's cost. 3. The last item in the row is a node name/description. Only important nodes have names. # ---- display cost matrix ------------------------------------------ def display_costs_matrix(costs,title=None): if title is not None: print(f'title: {title}') for node in costs: print(f'node # {node[0]}') for out in node[1]: print(f' outbound connection: node={out[0]} cost={out[1]}') if node[2] is not None: print(f' name: {node[2]}') # ---- sort the cost matrix by connection costs --------------------- # ---- if it is not already sorted ------------------------- new_costs = [] for idx,data in enumerated(costs): sorted_by_cost = sorted(data[1], key = lambda c: c[1]) print(f'[{idx}] {sorted_by_cost}') new_costs.append([ data[0], sorted_by_cost, data[2] ])