从文本文件读入具有可变列的字典

Question

I'm currently learning about data mining and one of the examples in the ebook I'm reading had a dictionary to store every user and their ratings for a song. This is the initialization of the dictionary that was given.

users ={"Angelica": {"Blues Traveler": 3.5, "Broken Bells": 2.0, 
                "Norah Jones": 4.5, "Phoenix": 5.0, 
                "Slightly Stoopid": 1.5, 
                "The Strokes": 2.5, "Vampire Weekend": 2.0},

    "Bill":     {"Blues Traveler": 2.0, "Broken Bells": 3.5, 
                "Deadmau5": 4.0, "Phoenix": 2.0, 
                "Slightly Stoopid": 3.5, "Vampire Weekend": 3.0}, 

    "Chan":     {"Blues Traveler": 5.0, "Broken Bells": 1.0, 
                "Deadmau5": 1.0, "Norah Jones": 3.0, 
                "Phoenix": 5, "Slightly Stoopid": 1.0}}

I'm stuck on figuring out how to create this same dictionary if the same values were in a text file where each line contains the information of each user. This would be an example of the first line in the text file:

Angelica, "Blues Traveler": 3.5, "Broken Bells": 2.0, "Norah Jones": 4.5, "Phoenix": 5.0, "Slightly Stoopid": 1.5, "The Strokes": 2.5, "Vampire Weekend": 2.0

What I have so far:

with open(text_file) as f:
for line in f:
    songs = line.split(',')
    for current_song in songs
        ratings = current_songs.split(':')

I'm not too sure how create the dictionary. The nested dictionaries have been confusing me for a few hours.

Answer 1

users = {}

with open(text_file) as f:
    for line in f:
        parts = line.rstrip().split(', ')
        name = parts[0]
        users[name] = {}

        for rating in parts[1:]:
            song, score = rating.split(': ')
            song = song[1:-1]
            users[name][song] = score

print users

Answer 2

Can be made more concise with json library. We will do following:

1. First lets split the line and separate artists name and data. So, string Angelica, "Blues Traveler": 3.5, "Broken Bells": 2.0, "Norah Jones": 4.5,... is split into two strings Angelica and second string "Blues Traveler": 3.5, "Broken Bells": 2.0, "Norah Jones": 4.5,...

    username, songs = line.split(',', 1) 

2. If you observe carefully, the second string can be easily converted to a dictionary by importing it into json.loads , however it does not have { and } to make it a valid json. So we will add it manually and import it into json.

    songs = "{%s}" % songs json.loads(songs) 

So total code is:

import json

user = {}
with open('my.txt') as f:
    for line in f:
        username, songs = line.split(',', 1)
        songs = "{%s}" % songs
        user[username] = json.loads(songs)

print user