Make a string lowercase

# mb_strtolower

(PHP 4 >= 4.3.0, PHP 5, PHP 7, PHP 8)

mb_strtolower — Make a string lowercase

### Description

mb_strtolower(string `$string`, ?string `$encoding` = `null`): string

Returns `string` with all alphabetic characters converted to lowercase.

### Parameters

`string`

  The string being lowercased.

`encoding`

  The `encoding` parameter is the character encoding. If it is omitted or `null`, the internal character encoding value will be used.

### Return Values

`string` with all alphabetic characters converted to lowercase.

### Changelog

Version | Description
--- | ---
8.3.0 | Implemented conditional casing rules for the Greek letter sigma.

### Examples

Example #1 mb_strtolower() example

`<?php
$str = "Mary Had A Little Lamb and She LOVED It So";
$str = mb_strtolower($str);
echo $str; // Prints mary had a little lamb and she loved it so
?>`

Example #2 mb_strtolower() example with non-Latin UTF-8 text

`<?php
$str = "Τάχιστη αλώπηξ βαφής ψημένη γη, δρασκελίζει υπέρ νωθρού κυνός";
$str = mb_strtolower($str, 'UTF-8');
echo $str; // Prints τάχιστη αλώπηξ βαφής ψημένη γη, δρασκελίζει υπέρ νωθρού κυνός
?>`

### Notes

By contrast to strtolower(), 'alphabetic' is determined by 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 as a-umlaut (ä).

For more information about the Unicode properties, please see » http://www.unicode.org/reports/tr21/.

### See Also

- mb_strtoupper() - Make a string uppercase
- mb_convert_case() - Perform case folding on a string
- strtolower() - Make a string lowercase

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