Hướng dẫn first letter lowercase php

(PHP 5 >= 5.3.0, PHP 7, PHP 8)

lcfirst — Make a string's first character lowercase

Description

lcfirst(string $string): string

Note that 'alphabetic' is determined by the current locale. For instance, in the default "C" locale characters such as umlaut-a (ä) will not be converted.

Parameters

The input string.

Return Values

Returns the resulting string.

Examples

Example #1 lcfirst() example

$foo = 'HelloWorld';
$foo = lcfirst($foo);             // helloWorld$bar = 'HELLO WORLD!';
$bar = lcfirst($bar);             // hELLO WORLD!
$bar = lcfirst(strtoupper($bar)); // hELLO WORLD!
?>

See Also

• ucfirst() - Make a string's first character uppercase
• strtolower() - Make a string lowercase
• strtoupper() - Make a string uppercase
• ucwords() - Uppercase the first character of each word in a string

phpnet at katylavallee dot com ¶

13 years ago

Easiest work-around I've found for <5.3:


$string

alex aulbach ¶

13 years ago

In some cases maybe more useful?

$lower = strtolower( substr($upper,0,1) ) . substr($upper,1);

harmor ¶

14 years ago

A slight modification from Northie's post here ( http://us2.php.net/manual/en/function.ucfirst.php#68443), where lcfirst may not exist in your PHP build:

if(false === function_exists('lcfirst'))
{
    /**
     * Make a string's first character lowercase
     *
     * @param string $str
     * @return string the resulting string.
     */
    function lcfirst( $str ) {
        $str[0] = strtolower($str[0]);
        return (string)$str;
    }
}/* Tests */
echo var_dump(lcFirst(NULL)).'
';    /* string(0) ""  */
echo var_dump(lcFirst(''))  .'
';    /* string(0) ""  */
echo var_dump(lcFirst('S')) .'
';    /* string(1) "S" */
echo var_dump(lcFirst('É')) .'
';    /* string(0) "�" */
echo var_dump(lcFirst('Hello World!!!')); /* string(14) "hello World!!!"  */

ahlers_wim at hotmail dot com ¶

13 years ago

As of PHP release 6 direct reference modification is not permitted any more.
Reference modification is the process of manipulating characters within a string by means of the instruction such as:
$str[0] in the code line: $str[0] = strtolower($str[0]);

For this reason I have recoded the lcfirst function (on function_exists('lcfirst') === false) as follows:

if ( false === function_exists('lcfirst') ):
    function lcfirst( $str )
    { return (string)(strtolower(substr($str,0,1)).substr($str,1));}
endif;
?>

Remarks:
Also notice that I have used the more modern scope delimeters (if:-endif;) and I have also removed the unnecessary intermediate result. That is, the manipulation is returned directly.