Python: create a list of lists from a file

Question

File:

I'd like to create dictionary as follows:

{1:[[2,5], [3,1]], 2:[[4,10], [1,5]], 
 3: [[4,1], [1,1]], 4: [[2,10], [3,1]]}

I managed to achieve this:

{1: [['2,5'], ['3,1']], 2: [['4,10'], ['1,5']], 
 3: [['4,1'], ['1,1']], 4: [['2,10'], ['3,1']]}

Using the following code:

f = open("file.txt")
D = {}

for line in f:
    line = line.strip().split(" ")   
    for i in line:
        D[int(line[0])] = [[x] for x in line[1:]]
print D

So instead of [x] you want something like map(int, x.split(','))? — jonrsharpe
– jonrsharpe, Commented Aug 13, 2015 at 15:31
I want dict to look like exactly as the first one containing only integers in lists, just look the example. — Nikolay Gospodinov
– Nikolay Gospodinov, Commented Aug 13, 2015 at 15:32
I did "just look the example". So, have you tried what I just suggested?! — jonrsharpe
– jonrsharpe, Commented Aug 13, 2015 at 15:33

bbill · Accepted Answer · 2015-08-13 16:22:19Z

2

f = open("file.txt")
D = {}

for line in f:
    line = line.strip().split(" ")   
    for i in line:
        D[int(line[0])] = [[int(y) for y in x.split(',')] for x in line[1:]]
print D

Edit: tested. Should work fine :)

Because your original code contains a list comprehension I'm going to assume you understand them. All I did was turn [x] into [int(y) for y in x.split(',')]. I.e., ['3,4'] ->[3,4].

edited Aug 13, 2015 at 16:22

answered Aug 13, 2015 at 15:33

bbill

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1 Comment

SuperBiasedMan Over a year ago

Please consider editing your post to add more explanation about what your code does and why it will solve the problem. An answer that mostly just contains code (even if it's working) usually wont help the OP to understand their problem.

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