字符串函数
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lcfirst

(PHP 5 >= 5.3.0)

lcfirst — Make a string's first character lowercase

说明

string lcfirst ( string $str )

Returns a string with the first character of str , lowercased if that character is alphabetic.

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

参数

str

The input string.

返回值

Returns the resulting string.

范例

Example #1 lcfirst() example

<?php
$foo = 'HelloWorld';
$foo = lcfirst($foo);             // helloWorld

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

参见

字符串函数
在线手册：中文 英文
PHP手册
PHP手册 - N: Make a string's first character lowercase

用户评论:

phpnet at katylavallee dot com (02-Apr-2009 04:50)

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

$string = "CamelCase"
$string{0} = strtolower($string{0})
echo $string; // outputs camelCase

?>

ahlers_wim at hotmail dot com (23-Nov-2008 05:48)

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:

<?php
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.

alex aulbach (06-Oct-2008 05:20)

In some cases maybe more useful?

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

harmor (05-May-2008 11:43)

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:

<?php

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)).'<br />';    /* string(0) ""  */
echo var_dump(lcFirst(''))  .'<br />';    /* string(0) ""  */
echo var_dump(lcFirst('S')) .'<br />';    /* string(1) "S" */
echo var_dump(lcFirst('?')) .'<br />';    /* string(0) "?" */
echo var_dump(lcFirst('Hello World!!!')); /* string(14) "hello World!!!"  */