PHP Program to Check if a Given String is Pangram or Not

<?php 

function isPangram($str) { 
	
	// Convert the string to lowercase 
	// for case-insensitive comparison 
	$str = strtolower($str); 

	// Initialize an array to track the 
	// presence of each letter 
	$letters = array_fill(0, 26, false); 

	// Iterate through each character in 
	// the string 
	for ($i = 0; $i < strlen($str); $i++) { 
		$char = $str[$i]; 

		// Check if the character is an 
		// alphabet letter 
		if (ctype_alpha($char)) { 
			
			// Mark the corresponding letter 
			// as present 
			$letters[ord($char) - ord('a')] = true; 
		} 
	} 

	// Check if all letters are present 
	// in the array 
	return !in_array(false, $letters); 
} 

// Driver code 
$str = "The quick brown fox jumps over the lazy dog"; 

if (isPangram($str)) { 
	echo "String is a pangram."; 
} else { 
	echo "String is not a pangram."; 
} 

?>

<?php 

function isPangram($str) { 
	
	// Convert the string to lowercase for 
	// case-insensitive comparison 
	$str = strtolower($str); 

	// Initialize an empty set to track 
	// unique letters 
	$lettersSet = []; 

	// Iterate through each character in 
	// the string 
	for ($i = 0; $i < strlen($str); $i++) { 
		$char = $str[$i]; 

		// Check if the character is an 
		// alphabet letter 
		if (ctype_alpha($char)) { 
			
			// Add the letter to the set 
			$lettersSet[$char] = true; 
		} 
	} 

	// Check if the set contains all 26 letters 
	return count($lettersSet) == 26; 
} 

// Driver code 
$str = "The quick brown fox jumps over the lazy dog"; 

if (isPangram($str)) { 
	echo "String is a pangram."; 
} else { 
	echo "String is not a pangram."; 
} 

?>

<?php 

function isPangram($str) { 
	
	// Convert the string to lowercase for 
	// case-insensitive comparison 
	$str = strtolower($str); 

	// Convert the string to an array 
	// of characters 
	$chars = str_split($str); 

	// Use count and array_unique to get 
	// unique letters 
	$uniqueLetters = count(array_unique( 
		array_filter($chars, 'ctype_alpha') 
	)); 

	// Check if there are 26 unique letters 
	return $uniqueLetters == 26; 
} 

// Driver code 
$str = "The quick brown fox jumps over the lazy dog"; 

if (isPangram($str)) { 
	echo "String is a pangram."; 
} else { 
	echo "String is not a pangram."; 
} 

?>

<?php 
  
function isPangram($str) { 
      
    // Convert the string to lowercase for 
    // case-insensitive comparison 
    $str = strtolower($str); 
  
    // Initialize a variable to track presence of letters 
    $checker = 0; 
  
    // Iterate through each character in 
    // the string 
    for ($i = 0; $i < strlen($str); $i++) { 
        $char = $str[$i]; 
  
        // Check if the character is an 
        // alphabet letter 
        if (ctype_alpha($char)) { 
              
            // Find the position of the letter in the alphabet 
            $pos = ord($char) - ord('a'); 
              
            // Set the corresponding bit to 1 
            $checker |= (1 << $pos); 
        } 
    } 
  
    // Check if all 26 bits are set 
    return $checker == (1 << 26) - 1; 
} 
  
// Driver code 
$str = "The quick brown fox jumps over the lazy dog"; 
  
if (isPangram($str)) { 
    echo "String is a pangram."; 
} else { 
    echo "String is not a pangram."; 
} 
  
?>