Question

IN PYTHON

Stretch

Remember that while it’s a good idea to have one person primarily responsible for typing (the driver) and the other reviewing each line of code and making suggestions (the navigator) you must switch roles after every problem.

1). List Construction

Write a Python program that prompts the user to enter a sequence of lowercase words and stores in a list only those words whose first letter occurs again elsewhere in the word (e.g., "baboon"). Continue entering words until the user enters an empty string ("", not " "), at which point your program should print the elements stored in the list, one word per line.

You may want to create a helper function that takes in a single string, and returns True if the first letter is repeated, or False otherwise. You could use a loop to do this, but you may also want to consider just using slicing and the in keyword, or the .count method.

Be sure to use an appropriate while condition here: while(True) might work in this case but it’s bad style.  

Example:

Enter a word: im

Enter a word: a

Enter a word: member

Enter a word: of

Enter a word: the

Enter a word: imperial

Enter a word: senate

Enter a word: on

Enter a word: a

Enter a word: diplomatic

Enter a word: mission

Enter a word: to

Enter a word: alderaan

Enter a word:

member

imperial

alderaan

2) Palindrome Check

Write a function named is_palindrome that will take a single string argument and return True if the argument is a palindrome (the letters appear in the same order the same forwards as they do backwards), False otherwise.   

You might want to consider writing a helper function for this problem to break up the steps, but it’s not required.

Hint: To remove punctuation and spaces, you could make a new empty string, loop through the characters in the original, and use the .isalpha() string method on each character to determine whether it’s a letter: only add characters that are actually letters to your new string.

Alternatively, you could use .replace and just replace any punctuation/spaces you find with the empty string.

Then convert the new string to lowercase and see if the modified string is equal to its reverse. Remember, you can easily reverse a string using slicing, or just write a helper function.

Example:

>>> is_palindrome('Abba')

True

>>> is_palindrome('Telat')

False

>>> is_palindrome("MadaM I'm Adam")

True

Answer 1

Here is the code:

def help_repeat(word):
    if(len(word) != 0):
        if(word[0] in word[1:]):
            return(True)
        else:
            return(False)
        

def list_construction():
    word_list = list()
    word = input('Enter a word: ')   # taking first input
    if(help_repeat(word) == True):   # checking the condition if the first letter reappears
        word_list.append(word)
    while(len(word) != 0):
        word = input('Enter a word: ')
        if(help_repeat(word) == True):
            word_list.append(word)
            
    for item in word_list:
        print(item)

# calling the function
list_construction()

----------------

def is_palindrome(words):
    words = words.replace("'","")   # removing ampersand
    words = words.replace(" ","")   # removing space
    words = words.lower()           # converting into lower case
    rev_words = words[::-1]         # reversing the word
    if(words == rev_words):
        return(True)
    else:
        return(False)

# calling the function
is_palindrome(input('Enter a word: '))

Here is the output:

---------

For any doubt, please comment below.