PHP - Function ctype_upper()

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The PHP Character type checkingctype_upper()checks whether the given string (text) contains only the uppercase letter. It will also check for white space. If the string contains any white space, even if all the letters are uppercase, it will be considered non-uppercase characters.

This function returns a boolean value true if the given string consists of only the uppercase letters; otherwise, it returns false. If the given string is empty (""), this function always returns false.

Syntax

Following is the syntax of the PHP Character type checking ctype_upper() function −

ctype_upper (mixed $text): bool

Parameters

This function accepts the following parameters −

• text (required) − A string needs to be tested.

Return Value

This function returns "true" if every character in the text is a uppercase letter, and "false" otherwise.

Example 1

If every character in the provided string (or text) is a uppercase letter, the PHP ctype_upper() function returnstrue−

<?php
   $string = "TUTORIALSPOINT";
   echo "The given string is: $string";
   echo "\nDoes string '$string' consists only uppercase letters? ";
   #using ctype_upper() function
   var_dump(ctype_upper($string));
?>

Output

The above program produces the following output −

The given string is: TUTORIALSPOINT
Does string 'TUTORIALSPOINT' consists only uppercase letters? bool(true)

Example 2

If every character in the provided string (or text) is not a uppercase letter, the PHP ctype_upper() function returns false −

<?php
   $string = "Hello World";
   echo "The given string is: $string";
   echo "\nDoes string '$string' consists only uppercase letters? ";
   #using ctype_upper() function
   var_dump(ctype_upper($string));
?>

Output

After executing the above program, the following output will be displayed −

The given string is: Hello World
Does string 'Hello World' consists only uppercase letters? bool(false)

Example 3

Checking multiple strings (texts).

In the example below, we create an array of a string containing multiple strings and, using the PHP ctype_upper() function to determine whether every character in strings is in uppercase −

<?php
   $strings = array('Tutorialspoint', 'TUTORIX', "INDIA");
   echo "The given strings are: ";
   foreach($strings as $text){
	   echo $text." ";
   }
   foreach ($strings as $test) {
      if (ctype_upper($test)) {
         echo "\nThe string '$test' consists of all uppercase letters.";
      }else {
         echo "\nThe string '$test' does not have all uppercase letters.";
      }
   }
?>

Output

Once the above program is executed, it will display the following output −

The given strings are: Tutorialspoint TUTORIX INDIA
The string 'Tutorialspoint' does not have all uppercase letters.
The string 'TUTORIX' consists of all uppercase letters.
The string 'INDIA' consists of all uppercase letters.

Example 4

If the provided string is empty (""), this function always returns false −

<?php
   $string = " ";
   echo "The given string is: $string";
   echo "\nDoes string '$string' consist only of uppercase letters? ";
   #using ctype_upper() function
   var_dump(ctype_upper($string));
?>

Output

Following is the output of the above program −

The given string is:
Does string ' ' consist only of uppercase letters? bool(false)