The sentence “A quick brown fox jumps over the lazy dog” contains every single letter in the English alphabet

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The sentence “A quick brown fox jumps over the lazy dog” contains every single letter in the English alphabet. Such sentences are called pangrams. You are to write a program which takes a sentence and outputs all the letters it is missing which prevent it from being a pangram. You should ignore the case of the letters in the input sentence, and your output should be all lowercase letters in alphabetical order. You should also ignore all non US-ASCII characters. In case the input sentence is already a pangram, output the string NULL. Input: Your program should read lines of text from standard input. Each line contains a sentence. Output: For each line of input, print to standard output all the letters it is missing, in lowercase, sorted in alphabetical order. If there are no missing letters, print the string NULL. Test 1 Test InputDownload Test 1 Input A quick brown fox jumps over the lazy dog Expected OutputDownload Test 1 Input NULL Test 2 Test InputDownload Test 2 Input A slow yellow fox crawls under the proactive dog Expected OutputDownload Test 2 Input bjkmqz TEST 2 works TEST one doesnt work , Any Help ? Code Below import string import itertools def get_missing_alphabets(s): if not isinstance(s,str): return None def ispangram(str): return sum(1 for i in set(str) if 96 string = ‘the quick brown fox jumps over the lazy dog’ if(ispangram(string1) == True): print(“NULL”) else: print(“No”) s=s.lower() alphabets=string.ascii_lowercase result=list(set(alphabets)-set(s)) result.sort() return “”.join(list(result)) print(get_missing_alphabets(“A slow yellow fox crawls under the proactive dog”))

The Correct Answer and Explanation is :

Let’s break down the task you’re trying to achieve and improve the given code to work properly for identifying missing letters in a sentence.

Task Understanding

You want to write a program that:

  1. Reads a sentence.
  2. Determines which letters of the English alphabet are missing.
  3. Outputs the missing letters in alphabetical order.
  4. If no letters are missing (i.e., the sentence is a pangram), it outputs NULL.

Problem with the Provided Code

There are several issues in the provided code:

  1. The ispangram function is incomplete.
  2. The check for missing letters is done incorrectly.
  3. The code doesn’t handle inputs effectively for both lower and uppercase characters.
  4. There’s unnecessary use of string.ascii_lowercase, which should be simplified to 'abcdefghijklmnopqrstuvwxyz'.

Plan to Solve

We can solve the problem in the following way:

  1. Normalize the input: Convert the sentence to lowercase and strip away non-alphabetic characters.
  2. Track missing letters: Create a set of all lowercase English letters ('a' to 'z'). Then, for each character in the input sentence, remove it from the set of all letters.
  3. Output the result: If any letters are left in the set, print them in sorted order. If the set is empty, print NULL.

Correct Code Implementation

Here is the corrected version of the code:

import string

def get_missing_alphabets(s):
    # Convert input sentence to lowercase and ignore non-alphabetic characters
    s = ''.join([char.lower() for char in s if char.isalpha()])

    # Define the set of all lowercase English letters
    all_letters = set(string.ascii_lowercase)

    # Create a set of letters from the input sentence
    sentence_letters = set(s)

    # Find the difference (missing letters)
    missing_letters = all_letters - sentence_letters

    # If there are missing letters, sort them and return as a string, else return NULL
    if missing_letters:
        return ''.join(sorted(missing_letters))
    else:
        return "NULL"

# Test the function with the provided sentences
print(get_missing_alphabets("A quick brown fox jumps over the lazy dog"))  # Expected output: NULL
print(get_missing_alphabets("A slow yellow fox crawls under the proactive dog"))  # Expected output: bjkmqz

Explanation of the Code

  1. Normalization: We use a list comprehension to filter and convert the string to lowercase, and we ignore non-alphabet characters with char.isalpha().
  2. Set Operations: We create a set of all lowercase letters using string.ascii_lowercase. We then subtract the set of characters in the input sentence from this complete set to get the missing letters.
  3. Output: If there are missing letters, they are sorted and returned as a string. If there are no missing letters, we return NULL.

Example Walkthrough:

  1. For the sentence “A quick brown fox jumps over the lazy dog”:
  • After filtering and converting to lowercase, the set of letters in the sentence will be {'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z'}.
  • All the letters of the alphabet are present, so the output will be NULL.
  1. For the sentence “A slow yellow fox crawls under the proactive dog”:
  • After processing, we find that the missing letters are {'b', 'j', 'k', 'm', 'q', 'z'}.
  • These letters are sorted and returned as bjkmqz.

Image of Code and Explanation

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Here’s an image of the Python code with a clear explanation. It should help clarify how the program works for identifying missing letters in a pangram. Let me know if you need further assistance!

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