Exercise 09-03:
Create a program that reads the files evens.txt and odds.txt and creates a single file evensandodds.txt with all the lines from the other two files in numerical order.
Answer:
##############################################################################
# Python From Scratch
# Author: Nilo Ney Coutinho Menezes
# Editora Novatec (c) 2010-2025 - LogiKraft 2025
# Site: https://pythonfromscratch.com
# ISBN: 978-85-7522-949-1 (Paperback), 978-85-7522-950-7 (hardcover), 978-85-7522-951-4 (ebook)
#
# File: chapter 09/exercise-09-03.py.py
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# Assume that even and odd files contain only integers
# Assume that values in each file are sorted
# Values don't need to be sequential
# Tolerates blank lines
# Even and odd files can have different number of lines
def read_number(file):
while True:
number = file.readline()
# Check if something was read
if number == "":
return None
# Ignore blank lines
if number.strip() != "":
return int(number)
def write_number(file, n):
file.write(f"{n}\n")
even = open("pares.txt", "r")
odd = open("ímpares.txt", "r")
even_odd = open("pareseimpares.txt", "w")
even_num = read_number(even)
odd_num = read_number(odd)
while True:
if even_num is None and odd_num is None: # End if both are None
break
if even_num is not None and (odd_num is None or even_num <= odd_num):
write_number(even_odd, even_num)
even_num = read_number(even)
if odd_num is not None and (even_num is None or odd_num <= even_num):
write_number(even_odd, odd_num)
odd_num = read_number(odd)
even_odd.close()
even.close()
odd.close()