将文本文件读入字典时出现问题

Question

I am a newbie in Python and would like to read a text file into a dictionary. The problem is that it reads in everything and only keeps the last record. I want to read in all the data and store everything in a Python dict .

It is just a simple text file reading and python data dictionary storing. Not sure why it does not work. Appreciate if someone can help.

book_data = {}

with open('test_data.txt', 'r', encoding='utf8') as raw_data:
        for item in raw_data:
            if ':' in item:
                key,value = item.split(':', 1)
                book_data[key]=value.lower()

test_data.txt

Book_ID: #111
Book_Title: Python 101
Book_description: This is a book about Python for beginners. 

Book_ID: #222
Book_Title: Java 101
Book_description: This is a book about  Java  for beginners. 


Book_ID: #333
Book_Title: Ruby 101
Book_description: This is a book about  Ruby for beginners. 


Book_ID: #444
Book_Title: C# 101
Book_description: This is a book about  C#  for beginners. 

My output is just one record instead of 4 records.

for k,v in book_data.items():
    print(k," : ", v)

Output:

Book_ID  :   #444

Book_Title  :   c# 101

Book_description  :   this is a book about  c#  for beginners.

Answer 1

You are overwriting each time, the key "Book_ID" for example, is first saved as 111, then 222, then 333 and then 444 by the time your print. You are probably using the wrong datastructure for your problem. If you wanted to use the id as a key, you should probably create a new dict for each for the objects and insert them into book_data with the ID as key

Answer 2

您每次迭代都会在book_data中重写相同键的值。

Answer 3

You're using three keys: Book_ID , Book_Title and Book_description . A dict can hold only one value for a key. You need to find a more suitable data structure to represent that file in memory.

What you probably want is a dict where the keys are 111, 222, 333, 444. And the value for each key would be another dict with keys Book_ID , Book_Title and Book_description .

Loop through the file, processing keys as you do now. But whenever you encounter an empty line, put the dict you have collected up to that point into a parent dict. Then continue scanning with an empty dict. At the end of the file, put the last dict into the parent as well.

Here's some skeleton code, taking into account the comments:

book_stash = {}

with open(...) as raw_data:
        for item in raw_data:
            if ':' in item:
                key,value = item.split(':', 1)
                if key == 'Book_ID':
                   book_data = {}
                   book_stash[value] = book_data
                else:
                   book_data[key] = value