(PHP 4 >= 4.3.0, PHP 5, PHP 7, PHP 8)
mb_convert_case — Perform case folding on a string
$string, int $mode, ?string $encoding = null): string
Performs case folding on a string, converted in the way specified by
mode.
stringThe string being converted.
mode
The mode of the conversion. It can be one of
MB_CASE_UPPER,
MB_CASE_LOWER,
MB_CASE_TITLE,
MB_CASE_FOLD,
MB_CASE_UPPER_SIMPLE,
MB_CASE_LOWER_SIMPLE,
MB_CASE_TITLE_SIMPLE,
MB_CASE_FOLD_SIMPLE.
encodingThe encoding
parameter is the character encoding. If it is omitted or null, the internal character
encoding value will be used.
A case folded version of string converted in the
way specified by mode.
| Version | Description |
|---|---|
| 7.3.0 |
Added support for
MB_CASE_FOLD,
MB_CASE_UPPER_SIMPLE,
MB_CASE_LOWER_SIMPLE,
MB_CASE_TITLE_SIMPLE, and
MB_CASE_FOLD_SIMPLE
as mode.
|
Example #1 mb_convert_case() example
<?php
$str = "mary had a Little lamb and she loved it so";
$str = mb_convert_case($str, MB_CASE_UPPER, "UTF-8");
echo $str; // Prints MARY HAD A LITTLE LAMB AND SHE LOVED IT SO
$str = mb_convert_case($str, MB_CASE_TITLE, "UTF-8");
echo $str; // Prints Mary Had A Little Lamb And She Loved It So
?>
Example #2 mb_convert_case() example with non-Latin UTF-8 text
<?php
$str = "Τάχιστη αλώπηξ βαφής ψημένη γη, δρασκελίζει υπέρ νωθρού κυνός";
$str = mb_convert_case($str, MB_CASE_UPPER, "UTF-8");
echo $str; // Prints ΤΆΧΙΣΤΗ ΑΛΏΠΗΞ ΒΑΦΉΣ ΨΗΜΈΝΗ ΓΗ, ΔΡΑΣΚΕΛΊΖΕΙ ΥΠΈΡ ΝΩΘΡΟΎ ΚΥΝΌΣ
$str = mb_convert_case($str, MB_CASE_TITLE, "UTF-8");
echo $str; // Prints Τάχιστη Αλώπηξ Βαφήσ Ψημένη Γη, Δρασκελίζει Υπέρ Νωθρού Κυνόσ
?>
By contrast to the standard case folding functions such as strtolower() and strtoupper(), case folding is performed on the basis of the Unicode character properties. Thus the behaviour of this function is not affected by locale settings and it can convert any characters that have 'alphabetic' property, such a-umlaut (ä).
For more information about the Unicode properties, please see » http://www.unicode.org/reports/tr21/.