How to convert a file into a dictionary?

You can also use a dict comprehension like:

with open("infile.txt") as f:
    d = {int(k): v for line in f for (k, v) in [line.strip().split(None, 1)]}

d = {}
with open("file.txt") as f:
    for line in f:
       (key, val) = line.split()
       d[int(key)] = val

This will leave the key as a string:

with open('infile.txt') as f:
  d = dict(x.rstrip().split(None, 1) for x in f)