PHP strtoupper Function | Make a String Uppercase

PHP strtoupper converts a PHP string to uppercase characters. In this article, we will discuss the PHP strtoupper Function. Also, we will discuss a few examples of using it.

Also, you can convert a string to lowercase characters using PHP strtolower Function.

Syntax

strtoupper ($string)

Parameters

The strtoupper function expects only one parameter. Pass the string you need to convert to uppercase as the parameter.

Return Value

The function returns a string after converting all alphabetical characters to uppercase.

Input: strtoupper('concatly')
Output: CONCATLY

Input: strtoupper('Brnging Knowledge Together'
Output: BRINGING KNOWLEDGE TOGETHER

Examples

Let’s consider a couple of examples of using the function.

Example 1: Simple String

You can pass an alphabetical string to the function and convert it to uppercase.

<?php

	$string = 'This is a mixed STRING 123';
	$uppercase = strtoupper($string);

	echo $uppercase;
	/* THIS IS A MIXED STRING 123 */

?>

Example 2: Array of Strings

You can use the PHP array_map Function to directly convert all the strings in an array to uppercase by passing strtoupper as the callback function.

<?php

	$arrayOfStrings = array(
		'String 1',
		'string 2 is lower',
		'another string'
	);

	$upperCaseArray = array_map('strtoupper', $arrayOfStrings);
	print_r($upperCaseArray);
	/*
	Array
	(
	    [0] => STRING 1
	    [1] => STRING 2 IS LOWER
	    [2] => ANOTHER STRING
	)
	*/

?>

Conclusion

We discussed the PHP strtoupper in this article. You can read more about it on the Official PHP Documentation. Also, you can read about more String Functions on Concatly.