Simple file to dictionary

Question

So I have the file below with the following values. What I am trying to do is to put these int values into a dictionary.

I want my dictionary to look something along the lines of...

graph = {0: [0,1,2,3,4],1: [1,2,3,4,5], 2: [3,4] .... and so on.

I am currently using code from the following question.

Python - file to dictionary?

But it is not doing exactly what I was hoping. Any help would be great.

*I am currently using code from the following question* - from which question? — aga, Nov 12 '13 at 07:28
There is no following question :) Take a look at collections.defaultdict with an empty list as the default value. Should do the trick — Rudy Bunel, Nov 12 '13 at 07:28

score 2 · Accepted Answer · answered Nov 12 '13 at 07:30

Use collections.defaultdict:

>>> from collections import defaultdict
>>> d = defaultdict(list)
with open('input.txt') as f:
    for line in f:
        k, v = map(int, line.split())
        d[k].append(v)


>>> d
defaultdict(<type 'list'>,
{0: [0, 1, 2, 3, 4],
 1: [1, 2, 3, 4, 5],
 2: [3, 4], 3: [3],
 4: [5],
 5: [0]})

With normal dict you can use [dict.setdefault][2]:

with open('input.txt') as f:
    for line in f:
        k, v = map(int, line.split())
        d.setdefault(k, []).append(v)

Simple file to dictionary

1 Answers1