Creating A Dictionary From Csv Data

I have a function that takes a CSV file and splits it into 3 values; isbn, author and title then creates a dictionary that maps isbn values to tuples containing the author and titl

Solution 1:

Use the csv module for easier and more efficient processing, and a dict comprehension:

import csv

defisbn_dictionary(filename):
    withopen(filename, newline='') as infile:
        reader = csv.reader(infile)
        return {isbn: (author, title) for isbn, author, title in reader}

Your code only created a dictionary per line and only printed the dictionary. You probably wanted to return the dictionary instead.

Using a dict comprehension not only makes the function more compact, it is also more efficient. The dictionary is created in one go, in C code, instead of in a Python loop adding keys and values one by one.

Solution 2:

You need to declare isbn_dict before the loop, like this:

def isbn_dictionary(filename):
    file = open(filename, 'r')
    isbn_dict = {}
    for line in file:
        data = line.strip('\n')
        author, title, isbn = data.split(',') 
        isbn_dict[isbn] = (author, title)
    print(isbn_dict)

This way, each item is added to the existing dictionary.