Python 101 Assignment 3 Solution 2

solution_2.py

import csv

# Open all required files with at once
with open('numbers.txt',   'r') as numbersfile, \
     open('birthdays.txt', 'r') as birthdayfile, \
     open('output.txt',    'w') as output:
    
    # Read in each line as a dictionary
    # https://docs.python.org/2/library/csv.html#csv.DictReader
    numReader  = csv.DictReader(numbersfile, fieldnames=['Name','Number'])
    bdayReader = csv.DictReader(birthdayfile, fieldnames=['Name','Birthday'])

    # Create writer object
    # https://docs.python.org/2/library/csv.html#csv.DictWriter
    dictWriter = csv.DictWriter(output, ['Name','Birthday','Number'])
    dictWriter.writeheader()

    # skip first line in each reader
    # https://docs.python.org/2/library/functions.html#next
    next(numReader)
    next(bdayReader)

    # Create a list of dictionaries
    # Can you figure out why I am choosing to build a list
    # instead of just looping through the iterators
    # that numReader/bdayReader outputs above?
    numRows  = [row for row in numReader]
    bdayRows = [row for row in bdayReader]

    # Nested loop to find matches and write to new file
    for num in numRows:
        for bday in bdayRows:
            if num['Name'] == bday['Name']:
                row = {
                    'Name'     : num['Name'],
                    'Number'   : num['Number'],
                    'Birthday' : bday['Birthday']
                }
                dictWriter.writerow(row)