PHP 8 reference · Multibyte String Functions

PHP mb_convert_case() Function

Change the case of a string with Unicode rules: upper, lower, title case or case folding for comparisons.

PHP 8 Since 4.3

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Syntax

mb_convert_case(string $string, int $mode, ?string $encoding = null): string

Parameter	Description
`string`	The input string.
`mode`	`MB_CASE_UPPER`, `MB_CASE_LOWER`, `MB_CASE_TITLE`, `MB_CASE_FOLD` and their `_SIMPLE` variants.
`encoding` optional	The character encoding; defaults to `mb_internal_encoding()` (UTF-8).

The converted string.

Title case with accentsTry it yourself

<?php
echo mb_convert_case("élise de la tour", MB_CASE_TITLE), "\n";

Output

Élise De La Tour

Case-insensitive comparisonTry it yourself

<?php
$a = mb_convert_case("Straße", MB_CASE_FOLD);
$b = mb_convert_case("STRASSE", MB_CASE_FOLD);
var_dump($a === $b);

Output

bool(true)

Version	Change
PHP 4.3	Added

mb_strtolower() · Convert a string to lowercase, including letters outside ASCII such as É, Ü and Cyrillic. The Unicode-aware strtolower().
mb_strtoupper() · Convert a string to uppercase, including letters outside ASCII such as é, ß and Cyrillic. The Unicode-aware strtoupper().
ucwords() · Uppercase the first letter of each word in a string. By default words are separated by spaces, tabs and new lines.
PHP Strings · tutorial