php判断字符串长度strlen()与mb_strlen()函数-PHP源码

$str=‘中文a字1符‘;
echo strlen($str);
echo ‘
‘;
echo mb_strlen($str,‘UTF8‘);
//输出结果
//14
//6
?>

$str=‘中文a字1符‘;
//计算如下
echo (strlen($str) + mb_strlen($str,‘UTF8‘)) / 2;
echo
//输出结果
//10
?>

//测试时文件的编码方式要是UTF8

$str='中文a字1符';

echo strlen($str).'
';//14

echo mb_strlen($str,'utf8').'
';//6

echo mb_strlen($str,'gbk').'
';//8

echo mb_strlen($str,'gb2312').'
';//10

?>

/**
* PHP获取字符串中英文混合长度
* @param $str string 字符串
* @param $$charset string 编码
* @return 返回长度，1中文=1位，2英文=1位
*/
function strLength($str,$charset='utf-8'){
if($charset=='utf-8') $str = iconv('utf-8','gb2312',$str);
$num = strlen($str);
$cnNum = 0;
for($i=0;$i<$num;$i++){
if(ord(substr($str,$i+1,1))>127){
$cnNum++;
$i++;
}
}
$enNum = $num-($cnNum*2);
$number = ($enNum/2)+$cnNum;
return ceil($number);
}

//测试输出长度都为15
$str1 = '测试测试测试测试测试测试测试测';
$str2 = 'aaaaaaaaaaaaaaaaaaaaaaaaaaaaaa';
$str3 = 'aa测试aa测试aa测试aa测试aaaaaa';
echo strLength($str1,'gb2312');
echo strLength($str2,'gb2312');
echo strLength($str3,'gb2312');

function msubstr($str, $start, $len) {
$tmpstr = "";
$strlen = $start + $len;
for($i = 0; $i <$strlen; $i++){
if(ord(substr($str, $i, 1)) > 127){
$tmpstr.=substr($str, $i, 3);
$i+=2;
}else
$tmpstr.= substr($str, $i, 1);
}
return $tmpstr;
}
echo msubstr("一二三天下致公english",0,10);

function msubstr($str, $start, $len) { //&＃545;
$tmpstr = "";
$strlen = $start + $len;
if(preg_match('/[/d/s]{2,}/',$str)){$strlen=$strlen-2;}
for($i = 0; $i <$strlen; $i++) {
if(ord(substr($str, $i, 1)) > 0xa0) {
$tmpstr .= substr($str, $i, 2);
$i++;
} else
$tmpstr .= substr($str, $i, 1);
}
return $tmpstr;
}

?>

function cc_msubstr($str, $start=0, $length, $charset="utf-8", $suffix=true)
{
if(function_exists("mb_substr"))
return mb_substr($str, $start, $length, $charset);
elseif(function_exists('iconv_substr')) {
return iconv_substr($str,$start,$length,$charset);
}
$re['utf-8'] = "/[/x01-/x7f]|[/xc2-/xdf][/x80-/xbf]|[/xe0-/xef][/x80-/xbf]{2}|[/xf0-/xff]

[/x80-/xbf]{3}/";
$re['gb2312'] = "/[/x01-/x7f]|[/xb0-/xf7][/xa0-/xfe]/";
$re['gbk'] = "/[/x01-/x7f]|[/x81-/xfe][/x40-/xfe]/";
$re['big5'] = "/[/x01-/x7f]|[/x81-/xfe]([/x40-/x7e]|/xa1-/xfe])/";
preg_match_all($re[$charset], $str, $match);
$slice = join("",array_slice($match[0], $start, $length));
if($suffix) return $slice."…";
return $slice;
}