PHP | ctype_upper() Function

PHP | ctype_lower() Function

Last Updated : 16 Apr, 2020

The ctype_lower() function is an inbuilt function in PHP which is used to check whether the given characters in the string is lower case or not. Syntax:

bool ctype_lower( string $text )

Parameters: This function accepts single parameter $text which holds the string that need to be tested. Return Value: This function returns TRUE if all characters of a string is a lowercase character in the current locale. Below programs illustrate the ctype_lower() function in PHP: Program 1:

php

<?php 

// PHP program to check the string contains
// all lower case characters or not
$strings = array('gfg123', 'geeksforgeeks', 'GfG'); 

// Loop to check the above three strings
foreach ($strings as $testcase) { 
    if (ctype_lower($testcase)) { 
        echo "Yes\n"; 
    } else { 
        echo "No\n"; 
    } 
} 
?>

Output:

No
Yes
No

Program 2:

php

<?php

// Declare a string
$str = "GeeksforGeeks"; 

$n = strlen($str); 

$count = 0;

for($i = 0; $i < $n; $i++) {
    if(ctype_lower($str[$i])) {
        $count++;
    }
}

echo "Totla number of lower case "
     . "character in string: "
     . $count;
?>

Output:

Totla number of lower case character in string: 11

Reference: https://www.php.net/manual/en/function.ctype-lower.php

PHP | ctype_upper() Function

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