php截取字符串的实例代码(支持utf-8)

分享下php中截取字符串的例子，支持utf-8格式。

1，截取字符串

<?php
$string="2006年4月我又长大了一岁！";
echo substr($string,1)."...";
//截取字符串
function SubstrGB($in,$num)
{
$pos=0;
$out="";
while($pos<strlen($in))
{
$c=substr($in,$pos,1);
if($c=="\n") break;
if(ord($c)>128)
{
$out.=$c;
$pos++;
$c=substr($in,$pos,1);
$out.=$c;
}
else
{
$out.=$c;
}
$pos++;
if($pos>=$num) break;
}
return $out;
} //by www.jbxue.com
echo SubstrGB($string,8) ;
?> 

2，截取中文字符

<?php
/**
* cut_string.php
* ------------------------------
* 截取中文字符.
* edit by www.jbxue.com
*/
function cut_str($string, $sublen, $start = 0, $code = 'UTF-8')
{
if($code == 'UTF-8')
{
$pa = "/[x01-x7f]|[xc2-xdf][x80-xbf]|xe0[xa0-xbf][x80-xbf]|[xe1-xef][x80-xbf][x80-xbf]|xf0[x90-xbf][x80-xbf][x80-xbf]|[xf1-xf7][x80-xbf][x80-xbf][x80-xbf]/";
preg_match_all($pa, $string, $t_string);
if(count($t_string[0]) - $start > $sublen) return join('', array_slice($t_string[0], $start, $sublen))."...";
return join('', array_slice($t_string[0], $start, $sublen));
}
else
{
$start = $start*2;
$sublen = $sublen*2;
$strlen = strlen($string);
$tmpstr = '';
for($i=0; $i<$strlen; $i++)
{
if($i>=$start && $i<($start+$sublen))
{
if(ord(substr($string, $i, 1))>129) $tmpstr.= substr($string, $i, 2);
else $tmpstr.= substr($string, $i, 1);
}
if(ord(substr($string, $i, 1))>129) $i++;
}
if(strlen($tmpstr)<$strlen ) $tmpstr.= "...";
return $tmpstr;
}
}
echo "<br>".cut_str($string,8,$start=0,$code='sdf') ;
?>