CODEWITHSUNDEEP
pythonpython-3.x
Srinabh
Srinabh

Reputation: 400

Adding multiple values to a dictionary based on a key

I want to create a graph of all the destinations from a point a to b For this i wrote the code

from sys import stdin
starting,ending=input().split()
startnodes=set()
flights=[]
for line in stdin:
    x,y,z=line.split()
    flights.append([x,y,int(z)])
    startnodes.add(x)
    startnodes.add(y)
graph={}

for i in startnodes:
    for j in flights:
        if i==j[0]:
            graph.update({i:{j[1]:j[2]}})
print(graph)

Input:

Bangalore Hyderabad
Bangalore Mangalore 50
Mangalore Hydrabad 40
Bangalore Hyderabad 10000
Bangalore Chennai 4000
Chennai Hyderabad 4000

Output:

{'Mangalore': {'Hydrabad': 40}, 'Bangalore': {'Chennai': 4000}, 'Chennai': {'Hyderabad': 4000}}

Expected Output

{'Mangalore': {'Hydrabad': 40}, 'Bangalore': {'Chennai': 4000,'Mangalore': 50}, 'Chennai': {'Hyderabad': 4000}}

The problem here is that i am expecting multiple Entries for the key 'Bangalore, but that isn't happening

Upvotes: 0

Views: 36

Answers (1)

ruhaib
ruhaib

Reputation: 649

Use this:

graph.setdefault(i, {}).update({j[1]: j[2]})

instead of this:

graph.update({i: {j[1]: j[2]}})

Upvotes: 2

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