I have a file comprising two columns, i.e.,

1 a 
2 b 
3 c

I wish to read this file to a dictionary such that column 1 is the key and column 2 is the value, i.e.,

d = {1:'a', 2:'b', 3:'c'}

The file is small, so efficiency is not an issue.

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)

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)]}

def get_pair(line):
    key, sep, value = line.strip().partition(" ")
    return int(key), value

with open("file.txt") as fd:    
    d = dict(get_pair(line) for line in fd)

By dictionary comprehension

d = { line.split()[0] : line.split()[1] for line in open("file.txt") }

Or By pandas

import pandas as pd 
d = pd.read_csv("file.txt", delimiter=" ", header = None).to_dict()[0]

Simple Option

Most methods for storing a dictionary use JSON, Pickle, or line reading. Providing you're not editing the dictionary outside of Python, this simple method should suffice for even complex dictionaries. Although Pickle will be better for larger dictionaries.

x = {1:'a', 2:'b', 3:'c'}
f = 'file.txt'
print(x, file=open(f,'w'))    # file.txt >>> {1:'a', 2:'b', 3:'c'}
y = eval(open(f,'r').read())
print(x==y)                   # >>> True

If you love one liners, try:

d=eval('{'+re.sub('\'[\s]*?\'','\':\'',re.sub(r'([^'+input('SEP: ')+',]+)','\''+r'\1'+'\'',open(input('FILE: ')).read().rstrip('\n').replace('\n',',')))+'}')

Input FILE = Path to file, SEP = Key-Value separator character

Not the most elegant or efficient way of doing it, but quite interesting nonetheless :)

IMHO a bit more pythonic to use generators (probably you need 2.7+ for this):

with open('infile.txt') as fd:
    pairs = (line.split(None) for line in fd)
    res   = {int(pair[0]):pair[1] for pair in pairs if len(pair) == 2 and pair[0].isdigit()}

This will also filter out lines not starting with an integer or not containing exactly two items

I had a requirement to take values from text file and use as key value pair. i have content in text file as key = value, so i have used split method with separator as "=" and wrote below code

d = {}
file = open("filename.txt")
for x in file:
    f = x.split("=")
    d.update({f[0].strip(): f[1].strip()})

By using strip method any spaces before or after the "=" separator are removed and you will have the expected data in dictionary format

import re

my_file = open('file.txt','r')
d = {}
for i in my_file:
  g = re.search(r'(\d+)\s+(.*)', i) # glob line containing an int and a string
  d[int(g.group(1))] = g.group(2)

Here's another option...

events = {}
for line in csv.reader(open(os.path.join(path, 'events.txt'), "rb")):
    if line[0][0] == "#":
        continue
    events[line[0]] = line[1] if len(line) == 2 else line[1:]