Check if a string is Pangrammatic Lipogram in Python

A Pangram is a string where every letter of the alphabet appears at least once. A Lipogram is a string where one or more letters are missing. A Pangrammatic Lipogram is a special case where exactly one letter is missing from the alphabet.

In this tutorial, we'll learn how to identify these types of strings in Python by counting missing letters.

Algorithm

To solve this problem, we need to ?

• Convert the string to lowercase for case-insensitive comparison
• Count how many alphabet letters are missing from the string
• Classify based on the count:
  • 0 missing ? Pangram
  • 1 missing ? Pangrammatic Lipogram
  • 2+ missing ? Lipogram

Implementation

import string

def solve(input_string):
    input_string = input_string.lower()
    missing_count = 0
    
    for character in string.ascii_lowercase:
        if character not in input_string:
            missing_count += 1
    
    if missing_count == 0:
        return "The String is a Pangram"
    elif missing_count == 1:
        return "The String is a Pangrammatic Lipogram"
    else:
        return "The String isn't a Pangram but might be a Lipogram"

# Test with different strings
test_strings = [
    "pack my box with five dozen liquor jugs",
    "to stay in this mortal world or by my own hand go to oblivion, that is my conundrum.",
    "the quick brown fox jumps over a lazy dog",
    "waltz, nymph, for quick jigs ve bud"
]

for test_string in test_strings:
    print(solve(test_string))

The String is a Pangram
The String isn't a Pangram but might be a Lipogram
The String is a Pangram
The String is a Pangrammatic Lipogram

How It Works

The function works by iterating through all 26 lowercase letters and checking if each one exists in the input string. Here's the step-by-step process ?

1. Normalize input: Convert to lowercase using lower()
2. Count missing letters: Use string.ascii_lowercase to check each letter a-z
3. Classify result: Based on how many letters are missing

Alternative Approach Using Sets

We can also solve this using set operations for better performance ?

import string

def solve_with_sets(input_string):
    alphabet_set = set(string.ascii_lowercase)
    string_letters = set(input_string.lower())
    
    missing_letters = alphabet_set - string_letters
    missing_count = len(missing_letters)
    
    if missing_count == 0:
        return "The String is a Pangram"
    elif missing_count == 1:
        return "The String is a Pangrammatic Lipogram"
    else:
        return "The String isn't a Pangram but might be a Lipogram"

# Test the set-based approach
print(solve_with_sets("the quick brown fox jumps over a lazy dog"))
print(solve_with_sets("waltz, nymph, for quick jigs ve bud"))

The String is a Pangram
The String is a Pangrammatic Lipogram

Comparison

Conclusion

Use character iteration for simple cases or set operations for better performance with large strings. Both methods effectively classify strings as Pangrams, Lipograms, or Pangrammatic Lipograms by counting missing alphabet letters.