ipp2_0_palindromes

#!/usr/bin/env python
# -*- coding: utf-8 -*-
# Filename: ipp2_0_palindromes.py
# Version: 1.0.0
# Author: Jeoi Reqi

"""
Description:
    - This script demonstrates "Chapter 2: Project #2 - Finding Palindromes" from the book "Impractical Python Projects" by Lee Vaughan.
    - The script searches an English language dictionary file for palindromes and prints them out.

Requirements:
    - Python 3.x
    - The following modules:
        - sys module
        - requests module

Functions:
    - download_dictionary(url, file_name):
        - Description:
            - Downloads a dictionary file from a given URL.
            - Parameters:
                - url (str): The URL from which to download the dictionary file.
                - file_name (str): The name to save the downloaded file as.

    - load_dictionary(file):
        - Description:
            - Opens a text file and turns its contents into a list of lowercase strings.
            - Parameters:
                - file (str): The name of the file to open.
            - Returns:
                - list: A list of lowercase strings containing the words from the file.

    - find_palindromes(word_list):
        - Description:
            - Finds palindromes in a list of words.
            - Parameters:
                - word_list (list): A list of words to search for palindromes.
            - Returns:
                - list: A list of palindromes found in the input word list.

Usage:
    - Ensure you have Python 3.x installed on your system.
    - Save the script to a file, for example, `palindromes.py`.
    - Run the script using the command: python palindromes.py.

Running the Script:
    - Open a terminal or command prompt.
    - Navigate to the directory where the script is saved.
    - Run the script using the command: python palindromes.py.

Output:
    - Upon running the script, any palindromes found in the dictionary file will be printed to the console.
"""

import sys
import requests

def download_dictionary(url, file_name):
    """
    Download a dictionary file from a URL.

    Parameters:
        url (str): The URL from which to download the dictionary file.
        file_name (str): The name to save the downloaded file as.
    """
    try:
        response = requests.get(url)  # Sending a GET request to the specified URL
        with open(file_name, 'wb') as f:  # Opening the file in binary write mode
            f.write(response.content)  # Writing the content of the response to the file
    except requests.RequestException as e:
        # Handling exceptions that may occur during the request
        print("Error downloading dictionary from {}: {}".format(url, e))
        sys.exit(1)  # Exiting the program with an error code if an exception occurs

def load_dictionary(file):
    """
    Open a text file & turn contents into a list of lowercase strings.

    Parameters:
        file (str): The name of the file to open.

    Returns:
        list: A list of lowercase strings containing the words from the file.
    """
    try:
        with open(file, encoding='utf-8') as in_file:
            # Opening the file with utf-8 encoding and reading its contents
            loaded_txt = in_file.read().strip().split('\n')  # Splitting the text into lines
            loaded_txt = [x.lower() for x in loaded_txt]  # Converting all words to lowercase
            return loaded_txt  # Returning the list of lowercase words
    except IOError as e:
        # Handling IO errors that may occur during file operations
        print("{}\nError opening {}. Terminating program.".format(e, file))
        sys.exit(1)  # Exiting the program with an error code if an exception occurs

def find_palindromes(word_list):
    """
    Find palindromes in a list of words.

    Parameters:
        word_list (list): A list of words to search for palindromes.

    Returns:
        list: A list of palindromes found in the input word list.
    """
    palindrome_list = []  # Initializing a list to store palindromes
    for word in word_list:
        if len(word) > 1 and word == word[::-1]:  # Checking if the word is a palindrome
            palindrome_list.append(word)  # Adding the palindrome to the list
    return palindrome_list  # Returning the list of palindromes

def save_to_file(palindrome_list):
    """
    Save list of palindromes to a file.

    Parameters:
        palindrome_list (list): A list of palindromes to save.
    """
    try:
        with open("palindromes_list.txt", "w", encoding="utf-8") as f:
            for palindrome in palindrome_list:
                f.write("{}\n".format(palindrome))  # Writing each palindrome to the file
        print("Palindromes list saved to 'palindromes_list.txt'.")
    except IOError as e:
        print("Error saving palindromes list: {}".format(e))

def main():
    dictionary_url = "https://inventwithpython.com/dictionary.txt"
    dictionary_file = "dictionary.txt"
    download_dictionary(dictionary_url, dictionary_file)  # Downloading the dictionary file
    word_list = load_dictionary(dictionary_file)  # Loading the dictionary into a list
    palindromes = find_palindromes(word_list)  # Finding palindromes in the dictionary
    print("Number of palindromes found = {}".format(len(palindromes)))
    print(*palindromes, sep='\n')  # Printing each palindrome on a new line
    save_option = input("Do you want to save the list of palindromes to a file? (y/n): ")
    if save_option.lower() == "y":
        save_to_file(palindromes)  # Prompting the user to save the list if desired

if __name__ == "__main__":
    main()  # Calling the main function when the script is executed