PHP – Make an upper case string using mb_strtoupper()

In PHP, mb_strtoupper() is a multibyte string function that converts all alphabetic characters in a string to uppercase. Unlike the regular strtoupper() function, it properly handles multibyte characters and various character encodings.

Syntax

string mb_strtoupper(string $string, ?string $encoding = null)

Parameters

mb_strtoupper() accepts two parameters: $string and $encoding.

• $string− The string being converted to uppercase.

• $encoding− The character encoding. If omitted or null, the internal character encoding value will be used.

Return Value

Returns a string with all alphabetic characters converted to uppercase.

Example

Here's how to use mb_strtoupper() to convert a string to uppercase −

<?php
    $string = "Hello World!, Welcome to online tutorials";
    $result = mb_strtoupper($string);
    echo $result;
?>

HELLO WORLD!, WELCOME TO ONLINE TUTORIALS

Working with Different Encodings

The function can handle different character encodings properly −

<?php
    // UTF-8 string with special characters
    $string = "café résumé naïve";
    $result = mb_strtoupper($string, 'UTF-8');
    echo $result . "<br>";
    
    // Without specifying encoding
    $result2 = mb_strtoupper($string);
    echo $result2;
?>

CAFÉ RÉSUMÉ NAÏVE
CAFÉ RÉSUMÉ NAÏVE

Conclusion

The mb_strtoupper() function is essential for properly converting multibyte strings to uppercase, especially when working with international characters. Always use this function instead of strtoupper() when dealing with UTF-8 or other multibyte encodings.