php字符串截取函数

php教程字符串截取函数
在php中有一款字符串截取函数substr但这款函数，只能截取英文不支持中文与其

它的混体，下面我们提供了三款函数，它们可以支持中英文混合体。

function syssubstr($string,$length,$append = false)
{
if (strlen($string) < = $length )
{
return $string;
}
else
{
$i = 0;
while ($i < $length)
{
$stringtmp = substr($string,$i,1);
if ( ord($stringtmp) >=224 )
{
$stringtmp = substr($string,$i,3);
$i = $i + 3;
}
elseif( ord($stringtmp) >=192 )
{
$stringtmp = substr($string,$i,2);
$i = $i + 2;
}
else
{
$i = $i + 1;
}
$stringlast[] = $stringtmp;
}
$stringlast = implode("",$stringlast);
if($append)
{
$stringlast .= "...";
}
return $stringlast;
}
}

$string = "";
$length = "18";
$append = false;
echo syssubstr($string,$length,$append);

字符串截取函数二

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);
  $tmps教程tr='';

  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;
 }
}

$str="新程php培训";
echo cut_str($str,8,0,'gb2312');

函数三

//截取utf8字符串
function utf8substr($str, $from, $len)
{
return preg_replace('#^(?:[x00-x7f]|[xc0-xff][x80-xbf]+)

{0,'.$from.'}'.
'((?:[x00-x7f]|[xc0-xff][x80-xbf]+){0,'.$len.'}).*#s',
'$1',$str);
}
?>

上面三款函数都很好对中文字符等进行截取了，好了不说多了这些都是来自于网络

。